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What is the most readable screen font?

What is the most readable screen font?



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Fonts (i.e. letters) that facilitate reading in print don't always read well on a computer screen. New fonts such as Verdana have been developed especially for screen presentation of text.

There is some research that compares the readability of those fonts that are available across most operating systems: Times, Arial, Helvetica and Arial. For example, this study found that Times New Roman can be read faster than Verdana.

But there are thousands of other fonts, and maybe one font not commonly shipped with any OS would be even more easily readable, or at smaller sizes. Of course no empirical research can include all fonts that exist, but maybe there is some research that goes beyond the common websafe fonts.

Have there been attempts to create the most readable screen font that were supported by empirical tests? Or is there empirical research into screen font readability including non-websafe fonts?


For print (Generally)

In his book Cashvertising, Drew Eric Whitman cites a 1986 study of fonts (printed on paper) that found only 12 percent of participants effectively comprehended a paragraph set in sans-serif type versus 67 percent who were given a version set in serif typeface…

In a test of three different fonts, two serifs (Garamond and Times New Roman) and one sans serif (Helvetica), he found

  • 66 percent were able to comprehend Garamond;
  • 31.5 percent Times New Roman, and
  • 12.5 percent Helvetica
    (out of a total of 1,010,000 people surveyed).

(Source)

On screen (Generally)

Several observations can be made regarding the examined font types. First, no significant differences in reading efficiency were detected between the font types at any size. There were, however, significant differences in reading time. Generally, Times and Arial were read faster than Courier, Schoolbook, and Georgia. Fonts at the 12-point size were read faster than fonts at the 10-point size. In addition, a font type x size interaction was found for the perception of font legibility. In general, however, Arial, Courier, and Georgia were perceived as the most legible.

For font attractiveness, Georgia was perceived as being more attractive than Arial, Courier, and Comic, while Times was perceived as more attractive than Courier. (Bernard, et al. 2002)

But it is not that simple

Dyslexia sufferers can have different requirements. Most of the recommendations come from associations for people with dyslexia and they agree in using sans-serif fonts. The British Dyslexia Association recommends

  • Use Arial, Comic Sans or, as alternatives to these, Verdana, Tahoma, Century Gothic, and Trebuchet
  • Most users prefer dark print on a pale background but colour preferences vary
  • Avoid green and red/pink as these are difficult for colour-blind individuals.
    (British Dyslexia Association, 2012).

Also

WebAIM also has articles and resources for those with accessibility in mind

References

Bernard, M. et al. (2002). A Comparison of Popular Online Fonts: Which Size and Type is Best? [Online]
Available at: Wichita State University Software Usability and Research Laboratory
http://usabilitynews.org/a-comparison-of-popular-online-fonts-which-size-and-type-is-best

British Dyslexia Association. (2012). Dyslexia style guide [Online]
Available at: http://www.bdadyslexia.org.uk/common/ckeditor/filemanager/userfiles/About_Us/policies/Dyslexia_Style_Guide.pdf


14 Answers 14

It really depends on a lot of factors such as what is the frequency of certain characters that you expect and what fonts are available to you.

I did a rudimentary by creating a program that iterated through all of the available fonts I had installed on my Windows box at the time and printed a line containing each printable ascii character on to the screen in each of these font's. I repeated the test as well with different font sizes.

The results as I recall them were that Segoe UI and Tahoma were the best with respect to space utilization and readability for UI purposes at 10pt and 9pt sizes. In the short term we settled on Tahoma since Segoe UI isn't freely available for operating systems below Windows Vista. If you don't need to support Windows XP or older an Windows OS or other a non Windows OS then I would definitely go with Segoe UI otherwise I would go with Tahoma if it's available and if all else fails try Verdana. See this list for a lineup of available Windows fonts as well as information about the best of use of each.

Keep in mind as well that starting with Windows Vista I believe, Microsoft now recommends using a 9pt font instead of a 10pt font for UI elements since the Sego UI font displays much clearer than other fonts at low resolutions especially on flat panel displays.

Depending on what platform you are developing for, you may also want to look at modifying font metrics if possible. In .NET with WPF I recall there being quite a bit of ways to modify how the text is rendered to allow for condensing the space between characters and to make the individual characters more narrow. Using this type of technique you can stick with whatever font you like and just tweak it's rendering to get the results you need.

With regard to your specific example graph that you provided: for this particular graph I would recommend pivoting it so the text most likely to be read is horizontal for more natural reading. I would also place the number so that it is inside the each bar of the bar graph when it will fit with a color that stands out against whatever background color is there thus increasing the space for other things such as the labels. Laying out the bar graph as rows would make it easier to read and also to print on multiple pages if necessary. If a row layout is not possible then creating a separate key for each item in the graph would probably be reasonable and that way each bar could be place closer together as well to save space. The key would allow each bar to be labeled such as A, B, C. or 01, 02, 03. for example and the key (layed out in rows somewhere else) would give more detailed information about each.

Remember, a chart or diagram is mainly useful for getting quick visual information. If it becomes too much of a burden to the user/reader your probably best off simplifying it, consolidating some of the details of the chart, or just provide more raw data in a more tabular form.

Here is a simple listing showing Arial, Segoe UI, and Tahoma fonts at various sizes. Notice that the relative space taken up by each font is different at different point sizes.

Update: I've added another comparison below which shows a more complete listing of common characters including capital and lower case letters in each of the previously mentioned fonts with the addition of Verdana and MS Sans Serif (default UI font in Windows prior to Windows 2000). Unfortunately and in response to bobsoap's recommendation for using Verdana, it is pretty clear that Verdana is about the worst compared to the other fonts at 9pt although keep in mind that this may not hold true for other point sizes. Also size isn't necessarily always the most important detail, sometimes it's more important that a font is readable at small sizes than whether it is more compact relative to another font.


What is the most readable screen font? - Psychology

A document or application is considered accessible if meets certain technical criteria and can be used by people with disabilities. This includes access by people who are mobility impaired, blind, low vision, deaf, hard of hearing, or who have cognitive impairments. Accessibility features in Adobe Acrobat, Adobe Reader and in the Portable Document Format (PDF) make it easier for people with disabilities to use PDF documents and forms, with and without the aid of assistive technology software and devices such as screen readers, screen magnifiers, text-to-speech software, speech recognition software, alternative input devices, Braille embossers, and refreshable Braille displays.

The Web Content Accessibility Guidelines (WCAG) 2.0 (ISO/IEC 40500:2012) and the PDF/UA (ISO 14289-1) standard cover a wide range of recommendations for making content more accessible to people with disabilities. One benefit of following these guidelines is that content becomes more usable for all users. For example, the underlying document structure that makes it possible for a screen reader to properly read a PDF out loud also makes it possible for a mobile device to correctly reflow and display the document on a small screen. Similarly, the preset tab order of an accessible PDF form helps all users—not just users who rely on the keyboard—complete the form more easily.

Overview of Portable Document Format (PDF)

The PDF format is the native file format of the Adobe Acrobat family of products. The goal of this format and these products is to enable users to exchange and view electronic documents easily and reliably, independently of the environment in which they were created. PDF relies on the same imaging model as the PostScript® page description language to describe text and graphics in a device-independent and resolution-independent manner. To improve performance for interactive viewing, PDF defines a more structured format than that used by most PostScript language programs. PDF also includes objects, such as annotations and hypertext links, that are not part of the page itself but that are useful for interactive viewing and document interchange.

A logical tagged structure tree is used within each document to provide a meaningful reading order for content, as well as a method for defining structural elements role and relationship to page content. Within this tag structure, other properties such as alternative text and replacement text can be provided.

Determine the Accessibility Path for each PDF Document

PDF files are created in a variety of ways, from a variety of applications, and for a variety of purposes. Achieving the desired accessibility goals for an individual PDF file requires understanding the nature of the PDF and its intended use. Adobe Acrobat Pro DC provides several tools including the Make Accessible Menu in the Action Wizard mode and the Accessibility Checker to assist authors in evaluating and fixing issues that can impact accessibility.

The Adobe Acrobat Pro DC Accessibility Guide: PDF Accessibility Repair Workflow document provides details on how to assess existing PDF files for accessibility. By following these procedures in the recommended order, authors can efficiently proceed through the analysis of a PDF file in a systematic fashion. Systematically ruling out or confirming certain characteristics found in a PDF file will guide the author to the most appropriate path for making an individual PDF document accessible.

Note: These Best Practices techniques require access to Adobe Acrobat Pro DC. Adobe Acrobat Reader DC and Adobe Acrobat Standard DC do not have the complete set of tools needed to create and validate PDF documents for accessibility.

Start with an Accessible Document

The PDF format is a destination file format. PDF files are typically created in some other application. Optimally document accessibility should begin in the native document format. For example, many documents are created in a word processing or desktop publishing application, and then exported as PDF documents. There many things that can be done in native document applications to support accessibility, such as adding alternative text for images defining structural headings, lists, and data tables providing document language and setting document properties such as titles. Adobe desktop publishing applications such as Adobe InDesign and Framemaker support these features, as well as other word processing applications such as Microsoft Word. For information on building accessibility into documents created with Adobe products visit the Adobe Accessibility website. To gain assistance on adding accessibility into Microsoft Word documents prior to conversion to PDF format please visit the Microsoft Enable website. Making the native document accessible allows for less work when changes are made to the native document and the PDF document is regenerated.

If the native document is not available, in most cases, the document can still be made fully accessible. Without accessibility in the native format there will likely be more manual work required in the PDF to properly tag the document. There are some items such as choosing sufficient contrast between foreground and background colors that must be implemented in the native document.

Characteristics of Accessible PDF files

Accessible PDFs include but are not limited to the following characteristics:

A document that consists of scanned images of text is inherently inaccessible because the content of the document is a graphic representing the letters on the page, not searchable text. Assistive technology software cannot read or extract the words in a graphical representation. Furthermore, users cannot select or edit the text or manipulate the PDF for accessibility. Scanned images of text must be converted into to searchable text using optical character recognition (OCR) before addressing accessibility in the document.

Fonts that allow Characters to be Extracted to Text

The fonts in an accessible PDF must contain enough information for Acrobat to correctly extract all of the characters to text for purposes other than displaying text on the screen. Acrobat extracts characters to Unicode text when you read a PDF with a screen reader or the Read Out Loud tool, or when you save as text for a Braille embosser. This extraction fails if Acrobat cannot determine how to map the font to Unicode characters.

Interactive Labeled Form Fields with Accessible Error Messages and No Timing

Some PDFs contain interactive forms that people fill out using a computer. To be accessible, form fields must be interactive that is, a user must be able to enter values into the form fields. Interactive PDF forms also have a defined tab order which allows users of assistive technology to use the Tab key in order to progress from one form field or interactive control to the next in a logical manner. Refer to the document Adobe® Acrobat® Pro DC Accessibility Guide: Creating Accessible Forms for complete details. Forms must provide identification, give tips on proper completion, and prevent errors. Form entry should not be timed unless the user can request more time.

Other Interactive Features: Hyperlinks and Navigational Aids

Navigational aids in a PDF — such as links, bookmarks, headings, a table of contents, and a preset tab order for form fields — assist all users in using the document without having to read through the entire document, word by word. Bookmarks are especially useful and can be created from document headings. These features can be accessed using the keyboard without relying on the mouse, and allow for multiple way for users to navigation content.

Document Language and Title Indication

Specifying the document language in a PDF enables some screen readers to switch the current speech synthesizer to the appropriate language, allowing correct pronunciation of content in different languages. Providing a document title allows the user to locate and identify the document.

Security that will not Interfere with Assistive Technology

Some authors of PDFs restrict users from printing, copying, extracting, editing or adding comments to text. The text of an accessible PDF must be available to a screen reader. Acrobat’s security settings can be set to protect document content while not interfering with a screen reader’s ability to convert the on-screen text to speech or Braille.

Document Structure Tags and Proper Reading Order

To read a document’s text and present it in a way that makes sense to the user, a screen reader or other text-to-speech tool requires that the document be structured. Document structure tags in a PDF define the reading order and identify headings, paragraphs, sections, tables and other page elements. The tags structure also allows for documents to be resized and reflowed for viewing at larger sizes and on mobile devices.

Alternative Text Descriptions for Non-Text Elements

Document features such as images and interactive form fields cannot be understood by the user of a screen reader unless they have associated alternative text. Though link text is available to screen reader users, it is possible to provide more meaningful descriptions via replacement (actual) text. Alternative text for images and tooltips can aid many users, including those with learning disabilities. Equivalents for multimedia, including any audio and video elements, must also be present.

Other Accessible Document Characteristics

There are additional characteristics of accessible documents including:

  • No reliance on color or sensory characteristics alone to convey meaning
  • Use of color combinations that provides a sufficient degree of contrast
  • Controls for audio
  • Use of text instead of images of text
  • No use of flashing or blinking elements
  • No focus changes without user initiation
  • Consistent navigation and identification of elements

Adobe Acrobat and Adobe Acrobat Reader Accessibility Features

Accessibility features in Adobe Acrobat DC and Adobe Acrobat Reader DC fall into two broad categories: features that make the reading of PDF documents more accessible, and features that help create accessible PDF documents. To create accessible PDF documents, you must use Acrobat Pro.

Features to Support the Reading of PDFs by People with Disabilities

All versions of Adobe Acrobat DC, Adobe Acrobat Reader DC, Acrobat Standard DC and Acrobat Pro DC provide support for the accessible reading of PDF files by persons with disabilities:

  • Preferences and commands to optimize output for assistive technology software and devices, such as saving as accessible text for a Braille printer
  • Preferences and commands to make navigation of PDFs more accessible, such as automatic scrolling and opening PDFs to the last page read
  • An Accessibility Setup Assistant Wizard for easy setting of most preferences related to accessibility
  • Keyboard alternatives to mouse actions
  • Reflow capability to temporarily present the text of a PDF in a single, easy-to-read column
  • Read Out Loud text-to-speech conversion
  • Support for screen readers and screen magnifiers
  • Support for high contrast and alternative foreground and background colors

Features to Support the Creation of Accessible PDFs

  • Creation of tagged PDFs from authoring applications
  • Conversion of untagged PDFs to tagged PDFs from within Acrobat
  • Security settings that allow screen readers to access text while preventing users from copying, printing, editing and extracting text
  • Ability to add text to scanned pages to improve accessibility
  • Tools for editing reading order and document structure
  • Tools for creating accessible PDF forms
  • Ability to set document properties including title and expose them through the title bar of the application

Though Acrobat Standard provides some functionality for making existing PDFs accessible, Acrobat Pro must be used to perform most tasks — such as editing reading order or editing document structure tags — that are necessary to make PDF documents and forms accessible (For more information see Comparison of Accessibility Features in Adobe Acrobat DC Plans).

The Acrobat Pro DC Accessibility Guide Series

Adobe has created a series of accessibility guides for Adobe Acrobat Pro DC to assist content authors in creating accessible PDF documents. There are four guides in this series:

PDF Accessibility Overview (this document)

The Adobe Acrobat Pro DC Accessibility Guide: PDF Accessibility Overview details what is meant by accessibility in the PDF file format. It distinguishes between the accessibility features of the file format, of Adobe Acrobat DC and of the Adobe Acrobat Reader application, and how the features of the software and the file format interact to achieve accessibility for people with disabilities.

Acrobat Pro DC PDF Accessibility Repair Workflow

The Adobe Acrobat Pro DC Accessibility Guide: PDF Accessibility Repair Workflow provides a step-by-step method for analyzing existing PDF files and making them accessible based upon that analysis. This workflow coincides with the workflow provided in the Make Accessible Action wizard and potential issues tested for in the Accessibility Checker tool.

Using the Accessibility Checker in Acrobat Pro DC

The Adobe Acrobat Pro DC Accessibility Guide: Using the Accessibility Checker describes the PDF accessibility checkers that are included in Adobe Acrobat Pro DC. Even if you generate an accessible PDF file from an authoring application such a word processor or desktop publishing program, you should then follow the steps in this guide in order to identify any items that may have been missed in the initial conversion, or to add PDF accessibility features that were not provided by the authoring tool.

Creating Accessible PDF Forms with Acrobat Pro DC

The guide entitled Adobe Acrobat Pro DC Accessibility Guide: Creating Accessible Forms describes how to use the forms tools within Adobe Acrobat Pro DC to add descriptions to form fields, tag untagged forms, set the tab order, manipulate tags and perform other PDF accessibility tasks. These techniques do not apply to PDF forms from Adobe LiveCycle Designer, as a separate process is provided for making LiveCycle forms accessible.


Typeface Readability

When reading text, most people do not read or parse individual characters or even words. Instead, the eye quickly scans through text and parses patterns and groups of characters (typically 6-9 characters at a time) which are nearly instantaneously converted into meaning by the human brain. This subconscious process allows us to read and understand text content very quickly with high degrees of understanding, even though we aren't even seeing or thinking of characters and words.

It is only when characters or words are unfamiliar or introduce a barrier to that direct pattern-to-meaning process that we must pause to more closely examine or process characters or words. For optimal readability and understandability, the key is to avoid those interruptions.

Some principles to consider:

  1. Use simple, familiar, and easily-parsed fonts.
  2. Avoid character complexity
  3. Avoid character ambiguity
  4. Use a limited number of typefaces, fonts, and font variations.
  5. Consider spacing and weight.
  6. Ensure sufficient, but not too much, contrast between the text and the background.
  7. Avoid small font sizes and other anti-patterns.

Use simple, familiar, and easily-parsed fonts

Simple, familiar typefaces are easiest to parse and read because the mind already has or can quickly generate a model for the shapes and patterns of text. Unfamiliar or complex typefaces require additional time and orientation, resulting in character or word parsing (which is slow and cognitively intense) rather than pattern/block parsing (which is fast and less burdensome).

There is not a best typeface or font. Experts disagree on which typefaces provide the best readability. Some long-held beliefs, such as the idea that sans-serif fonts are better for viewing on a screen and serif fonts are better for print are outdated due to the prevalence of high resolution displays. Regardless, simplicity in typefaces is critical. The typeface should be familiar or easily-parsed so that it quickly becomes familiar. Many common and standard fonts available in modern operating systems meet these requirements.

Similarly, there is not one typeface that will be optimal for all users with dyslexia.

Typefaces should be chosen to align with the tone, messaging, and brand of the content. A cartoon font used on a bank web site, for example, would likely undermine the sense of trust and professionalism the user expects. Consider the differences between these two logos with the same text, but different typefaces.

Which of these banks would you trust more with your money?

Avoid character complexity

Simpler shapes and patterns of typographical text are more quickly and accurately analyzed by the human mind. Be careful with complex fonts, especially for long sections of text.

Avoid character ambiguity

When glyphs or characters within a typeface appear similar to another, this can introduce ambiguity which must be processed by the brain, thus impacting reading speed and understanding.

The texts above illustrate common ambiguities. The capital letters "C" and "O" and lowercase letters "e" and "o" in the Arial typeface look very similar due to the very narrow opening in the letters. This is contrasted with the wider opening and more distinct differences between "C" and "O" and "e" and "o" in the Open Sans typeface.

Similarly, capital "I", lowercase "l", and numeral "1" appear almost identical in Gill Sans, but are much more easily distinguished from each other in Verdana. Even though Verdana is a bit more complex, this minor complexity helps with disambiguation of characters.

Use a limited number of typefaces, fonts, and font variations

Each time you encounter a new typeface, font, or font variation, your mind must build a map or model of the characters and patterns to then more quickly parse words and process meaning. This requires cognitive effort and time. If the typeface is already familiar, this overhead is reduced.

Be cautious when using multiple typefaces in the same document or web page. Ensure that typefaces/fonts align with types of content, such as one typeface or font for headings and another for body text.

Consider spacing and weight

Adequate letter and word spacing can improve readability by providing greater separation and clarity between adjacent characters and words. When letters or words appear very close to each other, confusion can be introduced.

Additionally, the weight (meaning the thickness of the glyphs) can also impact perceivability and readability.

WCAG requires that no loss of content or functionality occurs when the end user overrides page styles for paragraph spacing to 200% of the font size, text line height/spacing to 150% of the font size, word spacing to 16% of the font size, and letter spacing to 12% of the font size. Ensure that your page text can be modified without it disappearing or overlapping other page content.

Ensure sufficient, but not too much, contrast between the text and the background

Text is much easier to read when there is a sufficient contrast or brightness difference between the text and the background. The Web Content Accessibility Guidelines define measures for sufficient text contrast. Tools such as WebAIM's Color Contrast Checker make it easy to check contrast and determine WCAG compliance.

Black text on a white background is the default for web content, but this combination can feel stark and fatiguing, especially for long sections of text. Too much contrast may introduce halos or echos of text characters which can impact readability, especially for some with dyslexia. While WCAG does not have a maximum contrast threshold, you may want to style text with slightly lower contrast. This page, for example, uses a very dark grey body text color on white for slightly reduced contrast.

Avoid small font sizes and other anti-patterns.

In addition to text spacing, weight, and contrast, the size of text has a significant impact on readability. Although WCAG has no minimum font size requirement, it is still a valid usability consideration.

Relative font sizes (such as percents or ems) provide more flexibility in modifying the visual presentation compared to absolute units (such as pixels or points).

The font size chosen also impacts line length&mdashthe number of characters that appear per line. Line length and other text layout considerations are covered in WebAIM's Text/Typographical Layout article.

Be careful with longer sections of text that are entirely bold, italicized, capitalized, or styled in atypical ways. These font variations can make text more difficult to read&mdashand each new variation requires some orientation by the user.


A Guide to the Best Fonts for Legal Documents

Why do legal fonts matter? After all, you’ve worked hard to become a lawyer—not a designer. But did you know that the best legal fonts can better engage your audience, communicate more effectively, and impact how others perceive your law firm’s brand ? Also, some courts have outlined the fonts that they accept, which lawyers need to follow. Lawyers spend a vast amount of time drafting legal briefs, memos, court documents, and more every day. Paying attention to how the words look will help your legal writing stand out and persuade your reader better.

In this blog post, we’ll discuss why legal fonts matter in legal documents, and the best fonts and font sizes to use in legal documents and your law firm’s website. We’ll also include some tidbits on how understanding the difference between serif and sans serif fonts can help you select the right font.


White Text on Pure Black Backgrounds

There’s also reasons why you shouldn’t use a pure black background with white text. A pure black background kills all light emitting from the screen. This makes eyes work harder and open wider since it needs to absorb more light. When this occurs, the white letters can bleed into the black background and cause the text to blur. This effect is known as “halation” and it affects users with astigmatism, which people of all ages could have.

Instead of a black background, use a dark gray background so that more light emits from it and the text doesn’t bleed. Doing this decreases eye strain and strengthens reading stamina.


Transparent Type

The metaphor of &ldquotransparent type&rdquo was coined by Beatrice Warde, Monotype Imaging's famous marketing manager of the 1930s and 40s. She once wrote in an article that good type is like &ldquoa crystal goblet&rdquo which allows content to be more important than the container. Warde contended that the best types do not get in the way of the communication process: these faces are virtually invisible and allow words to make the statement&ndashnot the type. While this is sage advice, if this principle were followed rigidly, graphic communication would be about as exciting as a head cold. This does not mean that legible typefaces can&rsquot be distinctive in design, or that we should be using Ionic No. 5 for all typography. Some distinctive typefaces, such as Truesdell, Agfa Rotis, or Alinea, also make fine legibility fonts. The metaphor is, after all, a crystal goblet&ndashnot an empty jam jar.


What is the most readable screen font? - Psychology

Is it better when making a presentation with a Proxima(tm) type projector to use light/white text with a dark background or dark text with a light/white background?

The usual metaphor for screens (projection and computer) these days seems to be black type on a white background, that is, a paper metaphor. This sometimes results in video glare, with lots of rays coming from the background. Sometimes the old fashioned computer screen seems less tiring, showing lit-up text on a dead backround.

So you should try to reduce video glare, perhaps by reducing the figure/ground contrast. For example, our screens on this website usually have a light tint on the ground to reduce the electric blue-white video glare. Of course on the computer screen, one can just turn down the brightness control when working at night or in a darkened room. Television control rooms and airplane cockpits generally have darkened backgrounds upon which to display lighted data.

On paper, white type on a black background can result in filled-in serifs because of the printing process. It is also harder to read white type on a black ground (there surely must be some evidence about this). But we should never be working at the edge of legibility in any situation, so legibility tests might not be relevant.

For projection presentations, obviously the figure/ground contrast must be sufficient to overcome the ambient light. Check your presentation room out in advance, test your projectors, find out how to control the room lighting and the window curtains if necessary. You should simply look at the various design solutions under real conditions to see what is going on, and not depend on verbal discussions such as this to decide!

I frequently use white text on a black background, because it removes the "frame" around the image or text being shown. The frame conveys no information.

Further, the frame limits where things can be placed on the slide. Because we are used to margins in printed text, we expect some space between images / text and the projected frame (the paper metaphor E.T. referred to). By using a black background to remove the frame, an image can be made larger and thus more visible. This is particularly helpful if the image does not have the same proportions as standard slides (i.e., 2:3 for film slides 3:4 for computer screens, PowerPoint).

Other advantages to projecting white letters on a black background rather than vice versa:

Another good reason to have dark backgrounds and light lettering on PowerPoint slides is because of an optical illusion. Try this. Compare two shapes, say circles, of the same size, one white with a black background and one black against white. White against black always appears larger than black against white.

Hence, across America we see interstate highway signs with a dark green field and white lettering that "glows" when illunimated at night. In Beijing, China, where I teach, the street signs are dark blue with white lettering.

I recall an undergrad Psychology course from about 1971 in which the text authors claimed research showed black text on yellow paper was best for readability (comprehension?). The text used exactly that scheme: black text on yellow paper. Anyone else aware of this research? I have no idea who the authors were.

There is a great study from Stephen F. Austin State University in Texas on readability on the web. Read a summary here, or on Wikipedia.

Are there any different suggestions for longer term exposure to projected presentations? For example, every day for three weeks if you are on a training course. Should we change the colour every day to keep them interested? Should we change it for the period just after lunch when they become lethargic? Should it change to reflect the content or how they learn?

I am involved with the production of training courseware for military end users. As these courses are entirely computer based, the students may spend all day in front of the projector. The environment is controlled (lighting and such like) and standardised. We have followed the paper paradigm with black text on a white background for a number of reasons.

Primarily, because it is visually uncluttered (title, graphic, text). You have total continuity between screen and paper (we also have to produce the manuals to go alongside the presentations) which this also keeps printing costs down. It's quite a spartan approach (no watermarks, no background).

Can I make a plea for people to remember that not everybody has perfect eyesight. In my work I get involved in public talks to groups of all ages (literally from babes to 100 year olds) the fancy background so loved by many of the presenters at these events are not suitable for older members of the audience. And that's before one considers issues such as colour blindness.

In addition to the links given earlier for colour studies I use Vischeck to show me what pages will look like to those with colour blindness problems. There is a option there to test your own web page(s). Worth the effort. Not everybody has perfect eyesight like you.

I think that inclusive design has started to become more mainstream thinking recently, in many areas of design. The huge (in the UK) DIY company B+Q have a range of powertools designed to inlcude those with limited hand mobility (i.e arthritis). These are well designed regardless of the inclusivity brief and stand apart aesthetically and functionally (i.e. an electric screwdriver that you squeeze to operate). Inclusivity can lead to new ways of thinking and solving problems.

The RNIB (Royal National Institute for the Blind) launched guidelines for inclusive design for print. I am not sure how widely this has been used but it would be interesting to find out how this could lead current layout styles (small text vs big text).

Being partially colour blind myself, I tend to stick to black, white, red, green, blue, cyan, magenta and yellow. I also try and memorise colour codes of successful colours as looking at a colour gamut chart in photoshop is a no-go!

The recommendation for limiting eye strain on VDUs is to make the screen background a similar shade to the surroundings. For a projected image, then, a black background is preferable because it is exactly the same shade as the surroundings.

I use Trebuchet font, coloured 'ivory' (not white) on a plain black background. White text is good for subtle highlighting. The text goes right to the edge of the slide, but since the background is black, who misses the margin?

Everyone here seems to prefer light type on a dark background. There are reasons to disagree. Most typefaces including screen fonts are designed for black-on-white. Second, many talks are given under conditions where the presenter will have no control over lighting. White backgrounds ensure that there will be at least some light in the room. Third, in my own experience at scientific meetings, where one sees a weeklong succession of 15-20 minute talks, each prepared by a different person, the light type-on dark slides are *not* easier to read, and screen glare is a hypothetical, not actual problem.

One presenter points out that the background for a VDT should be close to the luminance of the VDT. At least for scientific talks, the object of interest very often ends up being a black-on-white data graphic embedded on the slide. A black slide background often contrasts brutally with the embedded data panels, and makes such figures much harder to resolve. A great deal depends on the specific slide layout and typography, but the hypothesized advantage suggested by many here does not, in my experience, exist.

Finally, the darker the room is, the easier it is to sleep, and the harder it is to make notes.

Regarding the matter of sleepiness:

From Tortora & Gabowski's Principles of Anatomy and Physiology, eighth edition:

Light = wakefulness is a double-edged sword. I meet many struggling college students in my job and the most common problem is sleep. I suspect spending too much time in front of a bright VDT late at night has something to do with this.

Use white backgrounds and keep the lights up in presentations. Send your kids to school with laptops, not desktops: at least they can close the screens.

Niels's post raises another reason why white backgrounds are preferable in presentations. Several optical aberrations are more severe in large-aperture systems compared to small- aperture systems of the same focal length. This is why most camera lenses have less contrast and resolution when used at full aperture (e.g., f/2) than when the aperture is closed (e.g., f/8). The same is true of the eye, which is why it is often possible for a person with myopia or astigmatism to read small print by squinting.

In dimmer light, the eye's aperture - the pupil - opens, and optical defects increase in severity. Hence as our vision deteriorates with age, we need brighter light to read by. The lesson for presentations seems obvious: dark backgrounds will result in dilated pupils and poorer vision. This effect should be worse for people with worse eyesight. At least that's the prediction. Quantitative tests of this notion would be straightforward and useful.

I give many presentations, lectures and trainings in a variety of settings, often to audiences diverse in age, ability, language comprehension, etc. I agree that the best choice is what works best in each individual location. However, it is a luxury to have that much time, information and control over the situation.

Using dark text on light backgrounds has almost always been the best choice for me. This is especially true when photocopies of the presentation are required and when other visual props and devices are also used.

The aberrations of the wide-pupil eye are the reason I switched from using white on black screens to black on white, even back in the days of DOS text screens. In addition, the white background "blooms" into the black letters, giving an impression of finer type and on graphs, finer lines. White on black letters seem bloated, by contrast.

However, nowadays I find that a pure white background is a bit harsh. I have set my Windows pallettes to emulate this website -- Tufte's ivory white.

A retired heart surgeon with many years of medical experience approached me with some wisdom about the color of projected backgrounds. He said that the light receptors (rod and cone cells) in the eyes of young and old alike are strained and become tired when forced to look at a brilliant white projected image in a very dark room environment. His advice was to do the following:

1. In venues where the room environment is dark, a stark white projected background creates a stronger more straining and single point of focus for our eyes. Therefore less strain on our eyes would be caused if the background were darker and the text lighter. I found this to be true.

2. On a computer screen in an environment where the general lighting conditions around your monitor are illuminated, the background color best serves the viewer with less strain on the eye by being a lighter color or value with the text being darker.

My observations over the last twenty years of designing and producing presentation visuals for projection, print, and computer are centered in three principles:

1. Design for the audience and the environment.

2. Make it as easy as possible for the audience to get the message.

3. Use a pallete of comfortable color contrasts that work to decrease eye strain.

For a long time I used a text editing program on the mac (intended mainly for programmers I think) that had a button to toggle between "day mode" and "night mode". You could customize the colors for each, but the idea was that "day mode" was dark-on-light and "night mode" was light-on-dark. I didn't always use this feature but it was nice to be able to quickly switch if I didn't like one or the other.

As a frequent presenter I've resolved this question for myself as, "It depends," finding that dark text / light background serves best in well-lit rooms, and light text / dark background serves best in darker rooms. For particularly important presentations when I do not have control of the lighting or can't predict what I'll find when I arrive, I will prepare two versions of a presentation, one light / dark and one dark / light, and use whichever best serves the context.

I also use a non-standard screen size -- a golden rectangle -- for my presentations. I do so to make certain projected images and slide layouts more visually compelling, but it only works with light backgrounds or with full-bleed images when the frame is obvious. Of course, with full-bleed images the question of background color ceases to be a question. With text rich slides (which I do not as a rule use) I would heed the counsel of other posters and go dark background to do away with the margin.

Finally, I might respectfully suggest that if we are too concerned with the readability of our text on-screen, or that eye strain may become an issue, this is a signal that the information is better served by a printed handout than an on-screen display. If there's one thing I took from ET's Cognitive Style of PowerPoint essay, it was (my paraphrase): "Pictures on screens, words on paper, unless the words serve as pictures."

Much of my work involves PowerPoint, and I've done a lot of work for companies presenting to government agencies. Usually, these meetings are held in hotel ballrooms, where the ambient light desaturates even the most colorful slides. After being asked to "brighten the slides", my attempts to satisfy the client by using the most saturated dark blue (R0, G0, B255) and by attempting to "brighten" the other colors still failed. Attempts to generate constrast by means of color were also unsatisfactory.

I attempted to solve this problem by using a strip of dark blue for the title area (R0, G0, B204) and by using plain white for the content area, but plain white introduces other limitations. For example, the apparent contrast of cyan (R0, G255, B255) on the dark blue mentioned above is quite different on plain white, when projected.

Consideration must be given to the relative luminance of the color choices. A green line (R0, G255, B0) and a red line (R255, G0, B0), when laid on a white field and projected in a venue with high ambient light, will appear surprisingly similar. When laid on a dark background, the differences are more apparent.

Digital projectors technically can project 16 million colors, however, in practical terms, the useful color range is much more limited. In conditions with high ambient light, background colors that use RGB values below a certain level are indistinguishable from black, which, in my experience, was roughly equivalent to a 60% black in print. Various "green" colors may project as indistinguishable from yellow colors with any amount of red in the RGB mix tend to project much darker than they appear on the computer screen. We usually test projectors with a test slide that contains various widths of rules and all the colors we're using in the presentation.

As a compromise between avoiding eye strain due to light glare caused by pure white on one hand and, on the other hand, the need for showing data plots and to make slide printouts (both of which look terrible on dark background), I second Tufte's use of an ivory background or also Michael's use of gray shades, with a little twist: try different shades of white, e.g., Cosmic latte, Cream, Ivory, Magnolia, Old lace, Seashell, Beige, Lemon Chiffon (see Wikipedia). Make sure you test these with a projector, not just your computer screen!

An interesting discussion!

I'd like to introduce another parameter: the light output of the image source. We have a facility that is in effect a very large, very bright rear-projection system with a really well-anchored black field in its dark state. The brightness of the system was set assuming that the ambient light in the room would be on, allowing the speaker to be clearly seen (based on the bias that the presenter should be the main focus of a presentation, generally) and allowing the other participants to see their notes, other participants, etc. Might the custom of turning off lights for projection be an accommodation for older generation projectors, from magic lanterns to Ektagraphic Carousels to recent small portable projectors?

Regardless of how we got here, people presenting white background slides in this facility with the lights subdued find that their audience is often vocally uncomfortable with how bright the slides were. Turning the ambient lights back on relieves this discomfort. Dark backgrounds with contrasting bright text are easier to look at as well.

What effect does the emergence of large, bright, self-lit displays (such as large flat-screen) have on the answer to the question posed?


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Great Blazing Colors ( Score: 5, Funny)

Re:Great Blazing Colors ( Score: 5, Funny)

Mustache Bold ( Score: 5, Funny)

Re:Mustache Bold ( Score: 5, Funny)

Sweeeeeeet. I've been waiting for this font for years.

Re:Great Blazing Colors ( Score: 5, Interesting)

For my shells, that I stare at for hours, I use:

It's usually green on black. I use yellow on black for special shells (like when I'm using a lot of shells with cssh). Putty defaults to white on black, so when I'm stuck in Windows land, that's it.

Any shells that default to black on white, I switch immediately. It's not so bad in a web browser, but there's something about a shell and typing in it that hurts my eyes. It could be that I'm concentrating that much more on the text on the screen, since it's usually fast data. Like, tail logs on a busy server, or run top with a refresh of 1 or 0. I catch details that other people don't even notice on their machines.

Re:Great Blazing Colors ( Score: 5, Insightful)

It's usually green on black.

Any shells that default to black on white, I switch immediately. It's not so bad in a web browser, but there's something about a shell and typing in it that hurts my eyes.

Re:Great Blazing Colors ( Score: 5, Informative)

Our eyes don't work like that -- they don't scan the visible spectrum from low to high, and see blue as the opposite end of red. Instead, we have receptors for certain colours, and base our colour perception on how much each of those get triggered. This is why colour blindness hits red/green or yellow/blue, despite those colours not being adjacent on the spectrum.

Our eyes can differentiate shades and hues of green better than any other colours -- this is an inherited survival trait from when it was important to see predators and distinguish ripe from almost-ripe. Blue, on the other hand, wasn't as important to survival, so we can't tell too many shades of blue apart, nor very far towards ultraviolet. We perceive indigo (the traditional indigo, not the "purple" that's called indigo these days) as a dark colour, for example, because it's at the edge of what we can see.

Re:Great Blazing Colors ( Score: 4, Funny)

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Re:Great Blazing Colors ( Score: 5, Informative)

534nm) but the L do not peak at red. The L cones have a peak sensitivity at about yellow-green (

We use red because red is way out the end of the visible spectrum and red light excites the L cones but not the M cones. If we were to use yellow-green we'd be exciting the M cones too much. The average person has about twice as many M cones than L or S cones, (we're very sensitive to green light) so yellow-green ends up exciting the M cones more than the L cones. By adjusting the amount of red (L cone excitation), green (M cone excitation) and blue (S cone excitation) we can replicate in the eye the cone response any visible colour would generate.

The human vision system is not like a camera - the cone response is only one part of a long and complex chain. Afterimages are somewhat a function of photo-pigment bleaching and later stages of visual processing in the nervous system and brain.

Cone response references:
Stockman, A. & Sharpe, L., "The spectral sensitivities of the middle- and long-wavelength-sensitive cone derived from measurements in observers of known genotype'', Vision Research, Volume 40, Issue 13, Pages 1711-1737, 16 June 2000

Re:Great Blazing Colors ( Score: 5, Funny)

A slashdot post citing references?

You, my friend, are way out of line.

Re:Great Blazing Colors ( Score: 5, Informative)

Good writeup. Found a simplified reference with a picture. I'm visual, don't you know-)

In terms of raw sensitivity, green produces the most signal at the lowest intensity. I've personally found that is true, and green on black is my usual choice I've tried them all, yellow is next best, which also fits the curve.

As PP points out, though, the visual system is complex, and the receptor distribution will vary for each person. It's also been found (no reference, sorry) that most people read words as a chunk, not by resolving and assembling the individual letters, so choice of font and kerning probably has more to do with readability than the color of the text.

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Wikipedia [wikipedia.org] has a good article describing this and the fact that our eyes are actually sensitive to blue, green and greenish/yellow. Red is what you see when the greenish yellow receptor is active but not the green, hence why we aren't all that sensitive to red light but very sensitive to yellow and green. Similarly if only the blue receptor is active you see a deep violet like what you get from a black light.

As far as monitors go, it's often easier on the eyes if you lower the color temperature to 6500K.

Re:Great Blazing Colors ( Score: 5, Interesting)

Yeah. That's also why unless you are colorblind, light yellow on a very dark blue will probably be about as readable as it gets because it has both luma contrast (difference in rod response) and chroma contrast (the yellow hits the red and green cones hard with just a little on the blue cones, the blue hits the blue cones and barely registers on the others). Even if you're colorblind, the huge difference in contrast should be sufficient to make it reasonably readable.

The absolute worst, IMHO, is white on medium green. you know. road sign colors. Unreadable until you get right up to the things, by which time you end up cutting off the guy in the next lane to slam your car into the exit lane that should have been marked 200 feet earlier. -D

Re:Great Blazing Colors ( Score: 5, Insightful)

A lot of cities have started installing new road signs that are white on blue, or even a faint yellow on blue. They're also making the text paint reflective, but not the background blue. Unfortunately, the cost of replacing all the road signs is prohibitively expensive, but at least new ones going up are a lot easier to read.

I still wish someone would start requiring road signs to be sized appropriately for the speed of the roads. Speed limit signs are required to be larger in places where drivers go faster to give them additional distance (time) to be able to recognize the sign. Road signes need to do the same.

Additionally, we should have cross street hanging signs (the big ones hanging from traffic light wires) on every block in cities. Here in my city, it's hit and miss, some streets have them, others don't. if I'm in the left lane, there's little hope I can read a street sign, even when parked at a light. It's simply too far away to read 3" tall letters. especially on green backing.

Re:Great Blazing Colors ( Score: 5, Informative)

Re:Great Blazing Colors ( Score: 5, Informative)

Our eyes don't work like that -- they don't scan the visible spectrum from low to high, and see blue as the opposite end of red. Instead, we have receptors for certain colours, and base our colour perception on how much each of those get triggered. This is why colour blindness hits red/green or yellow/blue, despite those colours not being adjacent on the spectrum.

Yes, we have different color sensors, but this is beside the GP's point. The green response curve overlaps significantly with red and blue. See the spectral response here [ed.ac.uk]. Red/Blue flashing lights will cause a significant color contrast as they alternately hit one type of cone and then the other. Even though the response to blue is low, it is still an effective color to use because the human eye's response is logarithmic wrt to brightness (i.e. take the graph I linked above and take the log the y dimension). Even that's a simplification when you add rods to the mix, but that's a subject for another post or later research.

Our eyes can differentiate shades and hues of green better than any other colours -- this is an inherited survival trait from when it was important to see predators and distinguish ripe from almost-ripe. Blue, on the other hand, wasn't as important to survival, so we can't tell too many shades of blue apart, nor very far towards ultraviolet.

This is wrong. We can identify more hues of blue than any other color, followed by red, while the intermediate hue discrimination can be quite low. Green sucks because that cone's frequency response is highly correlated with parts of the other two, and thus it forms somewhat of a degenerate basis for describing a hue with the 3 weights. Google "Hue-discrimination curve" for more info.

The evolutionary argument for this has *no* good evidence supporting it, but has become a very vibrant meme (I won't call it a legend, since it is an unproven theory). Green is bright for a variety of potential reasons: (1) It's one of the easier pigments for synthesize biologically, (2) There's a lot of green light coming from the sun, (3) It's a good baseline from which to differentiate other colors (there's a lot of green in our environment), and (4) yeah maybe it could have to do with rotten/ripe fruit. I'd bank on the first two though, especially noting that our hue sensitivity in the green range sucks. Predators are best to detect via motion (primarily rods), and by non-green cones (predators are camouflaged best against rods, i.e. non color vision, i.e. luminance, which overlaps most with green). You can of course believe whatever theory you want, but please don't start speaking about one as being authoritatively true I know some evolutionary biologists like to extrapolate really far from the evidence, but it always hurts when they are wrong on some theory that gets discounted, since it gives creationists a hammer to bludgeon all of biology and science with. Please don't give them that ammo, and label speculation as speculation until there's real concrete evidence to show. For evolution of these traits, that means sticking mostly to the "what" and "how", and not claiming "why" except in the most general and statistically supportable terms.

We perceive indigo (the traditional indigo, not the "purple" that's called indigo these days) as a dark colour, for example, because it's at the edge of what we can see.

It's not just that its near the edge, it's more complicated with several factors: (1) The blue cones are not that sensitive, (2) there is no additive luminance response due to the other cones frequency response falling off completely at violet, and (3) the rods don't even respond to it very well (last point only really matters for

Re: ( Score: 3, Insightful)

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Re:Great Blazing Colors ( Score: 4, Interesting)

Red, being the longest wavelength of visible light (that lines up with a color receptor), carries farther especially in foggy, snowy, rainy, or other inclement conditions. This is why stop lights, stop signs, and tail lights are all red.

Blue, being the shortest wavelength of visible light (that lines up with a color receptor), is seen more vividly and in greater detail than other colors. "Ultra white" paper is actually tinted blue because of this, and many whitening laundry soaps are reactive on ultraviolet (which tickles the blue receptors without being visibly blue).

If you use a color calibration sensor, such as professional printers use, you will find that paper which is truly white in the scientific sense (equal strength responsiveness across the spectrum) seems kind of yellowish and bland compared to this ultra white stuff with it's big blue and ultraviolet spike.

I think this is why police lights are red and blue, red to carry in inclement conditions, blue to get your attention.

Re:Leopard OSX fonts a polychromatic and easy to r ( Score: 4, Informative)

Re:Leopard OSX fonts a polychromatic and easy to r ( Score: 5, Informative)

CRT pixels do not line up precisely with their r, g, and b light emission points, at least on most CRTs. If you look at a single white pixel on a field of black through a lupe, you'll see it's composed of a number of red, green, and blue dots, not one dot for each color. Look at a different pixel, and the exact pattern will be different (shifted a little).

They use a couple of electromagnetic coils in the rear of the tube to guide an electron beam to the right point on the CRT's surface, but it is not so precise on most models (though maybe some really high end stuff for scientific work) as to be able to exactly hit specific phosphorescent spots.

This is why sub-pixel rendering works on LCDs but not CRTs (which turn on and off [or shade] specific color points digitally), because we know the exact shape and color layout of each pixel.

Re:Leopard OSX fonts a polychromatic and easy to r ( Score: 5, Informative)

If you read the follow up you'll see that that is not a feature of Leopard, but the result of sub-pixel rendering. It's a technique for making text look better on LCDs.

Steve Gibson has an interesting article on it here:

Re:Leopard OSX fonts a polychromatic and easy to r ( Score: 3, Interesting)

Re: ( Score: 3, Informative)

Sub-pixel antialiasing might look sharper, but it'll always feel a bit out of place. I don't think it's easier to read. If you want bolder fonts, make them bolder, it's just that simple. If anything, sub-pixel precision is going to make them thinner.

On Windows font antialiasing makes fonts thinner but not on a Mac. On a Mac their goal is precision of the characters for print so the sizes and thinkness are correct although they look a little fuzzy on screen.

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Re:Great Blazing Colors ( Score: 5, Insightful)

Green on black terminal windows are the way they are for the same reason old oscilloscopes and radar displays were green on black - it's more cost effective to make a cathode ray tube that glows green. For a long damn time, all terminals came green-on-black, simply because that was the cheapest way to pair a CRT with a keyboard, and hardware terminals were what they used back before PC's were popular. Or invented.

The result of this was horrific eyestrain. Yes, some people can handle bright colored text on a black background. Most get eyestrain or worse, migraines. This is especially so if you switch from green-on-black to black-on-white (like a printed page).

Typists and transcriptionists and grad students and pretty much anyone who needed to refer to a printed reference hated it. In the early '80s, color monitors were pretty much crap for text (too fuzzy, not enough resolution) so there was a boom in the production of "amber" monitors. These used monochrome CRTs that phosphoresced a muted yellow-orange. This wasn't quite as jarring to the eyes.

Then someone came up with paper-white monochrome CRT's, and that was pretty much all she wrote for greenscreens.

Geeks keep it alive, because of nostalgia and tradition. It's looks high-tech and cool, because there was a time when it was high-tech and cool - and because there is an association with Unix, and by extension, Linux. What's more Unix than a DEC vt100 terminal hooked up to a PDP-11? Nothing. That's about as close to the metal as you can get without a soldering iron.

But, please, for the sake of your eyes and the eyes of others, don't pretend there is any inherent advantage to green-on-black for the vast majority of users.

Re: ( Score: 3, Interesting)

Bullshit.
Double bullshit.

First, what is more tiring, some glow, when most of the retina remains inactive picking 'dark', or a full blast from a CRT tube against your eyes?
There are these who prefer bright background with dark letters over the opposite, but I assure you you'll find few of these amongst CRT screen users, and the choice of white on black for office applications was to make it all resemble paper, the old known metaphor for 'surface for writing'. Not because it's easier on eyes.

Re: ( Score: 3, Interesting)

The result of this was horrific eyestrain. Yes, some people can handle bright colored text on a black background. Most get eyestrain or worse, migraines. This is especially so if you switch from green-on-black to black-on-white (like a printed page).

And it never occurred to you that this might be the fault of the colour scheme these people were switching to? I always have to turn down my brightness and contrast settings as low as possible to be even able to read Slashdot for more than a few minutes.

Re: ( Score: 3, Interesting)

Honestly, what a load of hogwash.

Green-on-black is perhaps the nicest thing to my eyes ever, though I am partial to Amber-on-black.

White on black hurts after a while. Black on White hurts more - I have a *MUCH* lower tolerance working with an IDE with a white paper colour than a black one. Of course, being a proper programmer, I use vi from a shell:)

Yes I actually used serial terminals for years, usually in the higher column mode - just because I could read more:)

I kinda miss hacking on the old CP/M bo

Re:Great Blazing Colors ( Score: 5, Interesting)

The retina doesn't get tired. it doesn't move.

The rest of the eye does as it tries to focus and refocus on a dark-but-not-dark environment, and the iris goes between contracting and expanding because it can't get a read whether it should be letting in more light because the background is too dark or contracting because the letters glow too bright, and the part of the brain running the ocular show will often make its displeasure felt in the form of splitting headaches.

For similar reasons, white text on a black background, while not as bad, isn't exactly good. This is why legal pads are pale yellow, and ledgers are pale green. Contrast is good, but too much contrast hurts.

Re:Great Blazing Colors ( Score: 5, Insightful)

"The retina doesn't get tired. it doesn't move."

Don't be pedantic. Tired doesn't just refer to muscle fatigue and retinas do indeed become less responsive without rest.

Re: ( Score: 3, Interesting)

I know a lot of geeks like dark working environments. However, it is well established that this is bad for your eyes in the

Personally I found that ( Score: 5, Informative)

. if black on white hurts your eyes, there's probably something else wrong there too. Not saying that black on white is optimal anyway, but it shouldn't be enough by itself to give you a headache or tire your eyes.

It generally boils down to: IMHO most people I've seen using computers are doing it wrong for their eyes.

For starters make sure you use a large enough, and clear enough, font so you don't have to squint. If you absolutely need 80 lines on the screen when editing sources, that's usually your clue that there's something wrong with your programming style (and I suspect for some people the short term memory too.) You shouldn't have methods that run over that many lines, unless they're truly trivial stuff. (Like, say, a long switch statement where each line does no more than delegate to a method of its own. Arguably there are better ways there too, but I don't find it to be the end of the world either.)

IDE's also offer a lot of tools to find the method you need, when you need it, and/or collaps/expand blocks so the don't take up screen estate when you don't need them. There's also stuff like showing you the parameters anyway, so you don't have to have a second window in which you look for the parameters to that method. And really lots of other stuff. Use those instead of cramming the absolute maximum lines of text on the screen.

When I see a couple of co-workers squinting at their 6 point Illegible Roman font in VI and doing greps manually in another illegible tiled window, heh, I'm just itching to tell them to move out of the stone age already. We even discovered this funky thing called the "wheel" in the meantime, ya know?

Clean your monitor regularly, especially if it's a CRT. CRT's have thick glass, and your eyes end up focusing back and forth between the dirt on the front side of it, and the letters on the back side of it. But it's distracting and tiresome on TFTs too. And if you need to squint because you're at the point of "is that a 'm' or a 'rn'? Or is it 'rh' behind that speck?" it's long overdue for a cleaning.

Do turn your contrast up, but turn your brightness down to a comfortable level. The monitor is not supposed to be an AA searchlight. Staring into very bright stuff, especially in a dark room, _is_ tiresome. Here especially the TFT's are the biggest offenders. The manufacturers got stuck on bragging about the brightness of their monitors, as if that's something good, and pre-set them to insanely bright levels. Turn that down to where you can live with the white for hours.

And it will be even more important when you have to focus on stuff that's the other way around: white on black. (Some websites love that scheme, for example.) On an ultra-bright monitors that will mean focusing on a mostly black screen, so your pupils are wide open, but some pieces of retina are getting to see some really bright letters. It's a recipe for a headache.

As a side-note, I'm genuinely surprised at how many people do the exact opposite. I've seen too many monitors which are turned to abysmal contrast, and as bright as halogen headlights. I mean, WTF? Some things are barely legible in that configuration.

Ok, so maybe it's good for PC games, where the average dev seems to think that every fucking thing must happen in nearly complete darkness. 'Cause, you know, we have 32 bit colours so we can display all the gamut of "black", "really dark", "dark grey", "room with a broken lightbulb" and "grey stone on a moonless night". But the brightness settings where you see in near dark in games, suck for work or even reading in a browser. If you use the same monitor for games, consider turning up the brightness or gamma up in those, instead of turning the monitor's brightness all the way to the right.

If you're stuck with a CRT, make sure it's a good one and properly tuned. Staring into an unfocused image, especially with small unfocused fonts, is a recipe for a headache.

Again, for CRT users, just because everything idiotically defaults to 60 Hz, is no

Re:Great Blazing Colors ( Score: 4, Interesting)

I usually use a dark grey on a medium or dark grey. Maybe something like #222222 on #777777. Enough contrast to read easily, easy on the eyes, and easy to focus on something else quickly.

White on black makes my eyes bleed, especially when trying to refocus quickly off-screen.

Re: ( Score: 3, Interesting)

Re: ( Score: 3, Interesting)

I'm also used to green on black. And green is better than yellow or white on CRT monitors which have convergence problems, because you don't have red and blue that need to converge to green. It's probably better even on LCD monitors when you need small fonts. Also, out of the three primary colors, green appears the brightest (human eye perceiving).

Anyway, I seem to be very confortable with black on white used by web browsers if no convergence problems exist (no old CRT).

In fact, given a good LCD monitor, black on white should be the best.
cleartype (or whatever subpixel rendering is named in your platform) is very good for providing nice easy to read letters. Full color works better with that rendering, so black on white whould be the best. Contrast should be high, and brightness should be adjusted to the lighting of the room. More light, more brightness.

The more it can look like paper, the better. Paper works great.

Re:Great Blazing Colors ( Score: 5, Insightful)

Because the screen directly emits light, it is typically more tiring to your eyes. That's why people often prefer light text on dark background for a screen. I generally choose "old school" green or amber on black.

Re: ( Score: 3, Interesting)

Re:Great Blazing Colors ( Score: 4, Informative)

I thought military used red on black so you don't lose your night eyes.

red on black is NOT easy on the eyes, as anyone who's owned a virtual boy can tell you.

Re:Great Blazing Colors ( Score: 5, Interesting)

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Eye-friendly color combination ( Score: 5, Funny)

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Re: ( Score: 3, Interesting)

White on white ( Score: 5, Funny)

I am and because of that ( Score: 5, Funny)

Re:But that's still not as funny as. ( Score: 5, Funny)

Colour? ( Score: 5, Insightful)

When you work with computers for long periods of time, the colour of the font is nothing compared with taking regular breaks. Look out the window. Go for a walk. Make some tea. Bump up the font size. Get a bigger monitor and put it further away.

You are focusing on a tiny, tiny, tiny piece of the problem. There are almost certainly a ton of ways in which you could reduce eyestrain by gigantic amounts in comparison without bothering with something as trivial as font colour.

Correct, also calibration and slashdot circa '01 ( Score: 3, Informative)

You gotta explain for us Americans. ( Score: 5, Funny)

Re:Refresh Rate ( Score: 5, Interesting)

indeed. it's insane how many CRT monitors are still operating at 60Hz when almost ALL of the hardware being used today is capable of higher rates.
For some of us with sensitive vision, looking at a 60Hz screen is like reading text written on a strobe light. Even if it doesn't subjectively bother you, it does cause increased eye strain. Apparently even OSHA cautions against 60Hz.
A good document on this issue ( show it to your librarian, IT pro, or whoever has locked you out of the control panel) is available here: http://www.nhpa.org/docs/ComputerMonitorFlicker.doc [nhpa.org]

Re: ( Score: 3, Informative)

Re:Refresh Rate ( Score: 4, Insightful)

It is probably true for those very old monochrome monitors that had like half a second of persistence, but it is definately not the case for color TVs. Yes, there is some persistency, but over 95% of the photons are emitted within a millisecond after the electron beam hits the phosphor, and the other 5% are emitted gradually over tens of milliseconds. The net effect is that there's sharp flashing, plus about 5% (in this example) of a more-or-less constant background. That is not going to improve the flicker a lot otherwise you could just point a lightbulb at your TV to increase the background illumination.

You can see the background light for yourself by taking a photo of a TV screen with a 1/200 exposure time.

What makes the flicker less obvious with a TV is that you normally watch a TV at 5-10 times the screen diagonal, and a computer monitor at only 2 times the screen diagonal, such that a much larger area of your field of view is covered by the screen. People are most sensitive to flicker at the edges of the field of view.

Re:mod parent up ( Score: 5, Funny)

Easiest ( Score: 5, Funny)

Re:Easiest ( Score: 5, Funny)

#000000 ( Score: 3, Insightful)

Black background font in black.

You know what? Just turn the monitor off and go look at something with depth-of-field.

Not color ( Score: 5, Interesting)

Re: ( Score: 3, Informative)

Seconded. Monitor at 50-60% bright, color temp at D50. Give your eyes a while to adjust (as in, give the cramps a while to subside), maybe a day or two.

I've still got my decent CRT from. 1998? 1998. Black-on-white for documents, green-on-black 10pt Courier for terminals, syntax coloring is ok mostly. I miss the layout tweaking I could do on Apple's Terminal line- and letterspacing with sliders let me get my setup Just Exactly Right. It matters.

Why, Pink of course ( Score: 5, Interesting)

Another webpage that makes effective use of colors ( Score: 3, Funny)

Green or Yellow on Black ( Score: 2, Informative)

A little more info please. ( Score: 3, Interesting)

There are so many variables to this.

  1. What medium are we referring to? CRT monitor, LCD monitor, printed matt page, Hi-gloss paper?
  2. How much ambient light is there?
  3. What type of ambient light is there? Incandescent, fluorescent, halogen.
  4. What is 'a long time'?
  5. Who are we talking about? A 7 year old child, a 30 year old office worker, a 50 year old proof reader.

Re:A little more info please. ( Score: 5, Informative)

If you are in a dark room, anything with a white background is waaay too bright, and light color on dark is preferrable. In a bright environment, on the other hand, the you see more reflections against a dark background, so you want to make your background bright, and the font color dark.

Easy answer ( Score: 2, Funny)

Don't you mean what colors? ( Score: 2, Troll)

Bright BLUE on vibrant RED . ( Score: 5, Funny)

Clarification needed ( Score: 3, Insightful)

What is "best" will clearly depend upon what criteria you consider. Are you talking about a combination that is teh least likely to lead to damage to the eyes, the combination which causes least pain while reading, or the combination that is most comfortable? Does psychological factors count? Is your userbase young, old, mixed? I would imagine the answer could differ depending on these cases.

The only thing I can tell for certain is that the claim that looking at black on white text on a screen is like starring into a light bulb is complete nonsense, and it is very easily confirmed that the two are nowhere near the same by simply looking into a light bulb ( thou it is probably best to limit such experiments in order not to damage your eyes ). While your pupils can somewhat adjust for the incoming light, starring into a light bulb at short distance will almost certainly overwhelm your eyes with light, while looking at the computer screen does not.

The fact that a computer screen emits light does not in itself mean it will be "brighter" than a paper. It can as an example be very difficult to read some LCD screens outdoors because the relatively faint light they emit is completely drowned by bright sunlight reflected off it's surface. Now, while it may or may not be true that it is "not good" to have all light coming from only one place in front of you (which would appears to suggest having a lit computer screen in a dark room is bad ), this could be easily avoided by simply adjusting the surrounding illumination and screen brightness, and I find it very doubtful that there is much a web designer can do to optimise his webpage for every single situation since users will change the brightness and contrast of their monitors.

As a pure guess, I would imagine that weather your color scheme is familiar, if your font is large enough, and the reader's "taste" has a much greater impact than most physiological effects, and thus I would recommend a black on white color scheme with a clear simple font of sufficient size. Most people find it acceptable, and there is as far as I know little evidence that it should be troublesome.

A serious response. ( Score: 5, Interesting)

Re:a serious response. ( Score: 4, Insightful)

Actually, the problem is, people don't use light-on-dark properly, which makes it even harder on the eyes. If you use a thin font like Heveltica or Arial, white-on-black causes the letters to turn into a light grey. The thing is, the black "creeps" onto the lighter color. The general hints have been to either use bold, which fattens the letters enough to offset some of the creep, make the font size larger, or choose a fatter font. All of this helps offset the creep - it's only at the larger sizes does the effect of the creep become less noticeable. It's why I hate when Courier is used as a default font - it's damn hard to read on a black background. On Windows boxes, I much prefer the fat and easily read FixedSys.

But there are tons of contrasty color combinations. White-black is generic and isn't eyecatching, but great for long sessions. Colors like Yellow-on-Blue are easily read, and the blue doesn't actually "creep" into the yellow too badly. Yellow-Red and Yellow-Green work well too. But yellow can be quite tiring to read.

Re: ( Score: 3, Informative)

Actually we see yellow, green and blue. We perceive red by the yellow cone being active in the absense of green. Pure blue appears as a deep violet (i.e. a blacklight). Some women have two different yellow receptors (which are on the X chromosome) and there is some variance between people for yellow.

Depends on the environmental light ( Score: 2, Interesting)

For different working environment, e.g. with different "general background" color/brightness, you may need different color combination.

Well, nothing could prevent the eyes' fatigue if you keep on looking at the screen too long.

Well at least we're all on the same page ( Score: 4, Interesting)

. because none of us have RTFA - as there isn't one.

Err, that's nice. Where's the links?

I prefer black on light gray ( Score: 2)

Answer: Whatever makes you feel the best ( Score: 5, Interesting)

I'll chime in as a physician.

I always wondered in medical school what causes eyestrain -- your mom probably told you "don't read in poor light," but since the photons are easily sufficient to give an image on your retina, this didn't make sense to me.

It turns out that your eye muscles have a difficult time obtaining a rapid and precise focus with poor light, which gives less contrasts on the edges that are detected for sharp focus. In low light conditions, the eye muscles are rapidly focusing back and forth, and these micro-contractions can fatigue them similar to the other large muscles of your body. As an analogy, imagine walking on level ground versus on a balance beam. You are constantly contracting different adjustment muscles to walk on a balance beam, using more energy and promoting fatigue.

So, in answer to your question, you would want a high-contrast color scheme to make it easy for your eyes to focus on the letters. "Duh," I hear you say.

Next, I would recommend minimizing the difference in brightness between your monitor and the outside environment and its background. That is, in a dark office have a dark monitor, and in a bright office, a bright one. Why? Well, same reason -- your eye muscles have to dilate your pupil every time you look away from a bright monitor to a dark monitor. More contractions / adjustments -> more fatigue. Not only that, but the high brightness contrast will give ineffective normalization of light across the eye receptors and could cause headache.

Regarding your study question -- difficult to fund, and difficult to accomplish. I guess you would have to divide several hundred office workers, and try to have them work the same hours under same conditions with different fonts, and then ask a subjective question regarding symptoms. It could be done, but I am not sure of any well-performed efforts that have addressed this question.

In summary, I would just choose contrasting colors that you like or find subjectively pleasing, and then keep the brightness on your monitor appropriate for ambient lighting. Also, don't forget to focus on the numerous other ergonomic factors on your workstation. I see a *lot* of people with bad backs from the workplace, but there are a lot of 80 year old secretaries that are not blind.

Cue the contempt for expertise from the anti-intellectual crowd now.:p

Re:Answer: Whatever makes you feel the best ( Score: 4, Funny)

You are on the right track but there is more ( Score: 5, Interesting)

You are on the right track but there is more. Yes, higher contrast is better than lower contrast. But how this works with color is complicated.

One big issue is that the eye is not perfect optically. It cannot focus all colors at the same focal plane. Just how well it does varies by individual and the optical conditions of their eyes, and the quality of corrective lenses (which usually make it worse with respect to the ability to simultaneously focus all colors).

An important factor to consider here is which color or colors the difference is at the edge being focused on. For example in the "hot dog" pattern that has been mentioned in a reply here, the difference is actually in green. If the red level of the yellow part is exactly the same as the level of the pure red part, then all the difference is in green and this is an issue of green contrast. Yellow on red like this is essentially the same as green on black. except that the extra red light with yellow on red causes the iris to close down more than the darker green on black would.

I find blue to be the worst to focus with. That may be because my sources of blue light are not sufficiently narrow band in the spectrum. Being spread out over the spectrum, it basically comes in fuzzy. Blue is also lower in contrast.

Green (be it green on black or yellow on red or even cyan on blue) is better.

Red seems to be the best in terms of focusing a sharp defining edge. You get red contrast with red on black or yellow on green or magenta on blue.

Unfortunately, effective contrast goes down when extra light is added in other colors. So you have to find a balance trading off the sharpness of the edge vs. the contrast. I've found a good compromise in orange on dark green (the level of green in the orange is the same value as the green background). Think of the orange in a neon sign on the green felt of a pool table. Then when I need to highlight something, I shift over to pink on cyan. basically add the same level of some blue to both the orange and the dark green.

A related issue is light quality when reading a book or newspaper. Usually we are stuck with black letters on white paper. The consideration is then what type of light. I find that incandescent light, or sunlight, works nearly best for me for long term reading. Fluorescent lighting is worse. Ironically, I find high pressure sodium vapor light is about as good as, and sometimes somewhat better than, incandescent light.

To understand this, look at the spectrum. Incandescent light has a fairly even level through all light wavelengths. This makes those black on white edges a bit fuzzy. But fluorescent light has two narrowband peaks at a red and green wavelength (the blue is broader). This can make the text edge sharper. twice. The eye ends up with two contrast edges. I believe this increases the eyestrain by causing the focus to be constantly jumping in and out to alternate the focus on the two different edges. It's a very small adjustment, but it is there at least for me. With incandescent light, it just settles in the middle of the fuzzy range and doesn't change much. And this is affected by how much light there is, which dictates how small the iris becomes. Higher light levels with a smaller iris won't change the effect from fluorescent as much as for incandescent, since with fluorescent the two contrast edges are already rather sharp due to the two narrowband spectral peaks. But for incandescent, the high light level helps (up to the point that intensity is too stressful).

This is why I believe we still need to keep some incandescent lighting around for reading and other close/fine work for long periods of time. I get a headache when working on things I need to look at closely when doing so under fluorescent light. The onset is about 25 to 45 minutes. I don't get the headaches under incandescent. And I have verified that the flicker is not the cause. White LEDs


  1. Well hinted font,
  2. Viewer that correctly interprets hinting,
  3. The font has good math typography,
  4. Sans Serif is usable only for presentations.

That's what Font hinting is. And here is a good example found in Google:

And here is a comparison between Adobe Reader (left) and Sumatra PDF (right):

Adobe Reader renders better, even if the font used (CM-Super) doesn't have the best hinting possible.

And here is what good math typography means. Hidden defects in mathdesign Blackboard Bold:

And yes, thats not a defect in the viewer, they print as seen from any reader. That means, it's good to use fonts with proven quality. Not to use something that in the last minute shows its hidden defects.

And finally the Sans Serif math. Can you easily read that? I can't.

If the font is large enough, serif fonts are not an issue even on screen.

The predominant problem of serif fonts on screen is the rendering accurate of the tiny serifs without creating visual clutter. But with modern displays, modern font rendering techniques (ClearType anti-aliasing and proper hinting) and large fonts, this is not an issue any more.

The advice of using sans-serif fonts in favour of serif fonts is therefore outdated, and using serif fonts on screen has the same advantage that it has in print namely,

[…] that serifs help guide the eye along the lines in large blocks of text. [Source]

The only potential problem is that not all fonts were designed with screens in mind, and are therefore poorly adapted to ClearType rendering. A properly hinted font mitigates this.

Next-generation displays (Apple’s Retina Display) promise to make even that obsolete: their resolution is so high that the naked eye cannot distinguish individual pixels, and text looks as smooth as in high-quality print 1 .

For now, though, most displays in use still have comparably low resolutions and require properly hinted fonts for best rendering. So, in summary (for now): Use a large font that was designed for on-screen usage. Serif or sans serif is irrelvant.

For inspiration, look at the free fonts listed at the Google Web Fonts directory, especially Vollkorn or the Droid Serif font which was particularly developed with small font size in mind.

1 Ironically, the article does pretty much the opposite: it uses a small font which, though developed for on-screen usage, contains hinting errors and looks smudged:


Transparent Type

The metaphor of &ldquotransparent type&rdquo was coined by Beatrice Warde, Monotype Imaging's famous marketing manager of the 1930s and 40s. She once wrote in an article that good type is like &ldquoa crystal goblet&rdquo which allows content to be more important than the container. Warde contended that the best types do not get in the way of the communication process: these faces are virtually invisible and allow words to make the statement&ndashnot the type. While this is sage advice, if this principle were followed rigidly, graphic communication would be about as exciting as a head cold. This does not mean that legible typefaces can&rsquot be distinctive in design, or that we should be using Ionic No. 5 for all typography. Some distinctive typefaces, such as Truesdell, Agfa Rotis, or Alinea, also make fine legibility fonts. The metaphor is, after all, a crystal goblet&ndashnot an empty jam jar.


The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.

Great Blazing Colors ( Score: 5, Funny)

Re:Great Blazing Colors ( Score: 5, Funny)

Mustache Bold ( Score: 5, Funny)

Re:Mustache Bold ( Score: 5, Funny)

Sweeeeeeet. I've been waiting for this font for years.

Re:Great Blazing Colors ( Score: 5, Interesting)

For my shells, that I stare at for hours, I use:

It's usually green on black. I use yellow on black for special shells (like when I'm using a lot of shells with cssh). Putty defaults to white on black, so when I'm stuck in Windows land, that's it.

Any shells that default to black on white, I switch immediately. It's not so bad in a web browser, but there's something about a shell and typing in it that hurts my eyes. It could be that I'm concentrating that much more on the text on the screen, since it's usually fast data. Like, tail logs on a busy server, or run top with a refresh of 1 or 0. I catch details that other people don't even notice on their machines.

Re:Great Blazing Colors ( Score: 5, Insightful)

It's usually green on black.

Any shells that default to black on white, I switch immediately. It's not so bad in a web browser, but there's something about a shell and typing in it that hurts my eyes.

Re:Great Blazing Colors ( Score: 5, Informative)

Our eyes don't work like that -- they don't scan the visible spectrum from low to high, and see blue as the opposite end of red. Instead, we have receptors for certain colours, and base our colour perception on how much each of those get triggered. This is why colour blindness hits red/green or yellow/blue, despite those colours not being adjacent on the spectrum.

Our eyes can differentiate shades and hues of green better than any other colours -- this is an inherited survival trait from when it was important to see predators and distinguish ripe from almost-ripe. Blue, on the other hand, wasn't as important to survival, so we can't tell too many shades of blue apart, nor very far towards ultraviolet. We perceive indigo (the traditional indigo, not the "purple" that's called indigo these days) as a dark colour, for example, because it's at the edge of what we can see.

Re:Great Blazing Colors ( Score: 4, Funny)

Re: ( Score: 3, Interesting)

Re:Great Blazing Colors ( Score: 5, Informative)

534nm) but the L do not peak at red. The L cones have a peak sensitivity at about yellow-green (

We use red because red is way out the end of the visible spectrum and red light excites the L cones but not the M cones. If we were to use yellow-green we'd be exciting the M cones too much. The average person has about twice as many M cones than L or S cones, (we're very sensitive to green light) so yellow-green ends up exciting the M cones more than the L cones. By adjusting the amount of red (L cone excitation), green (M cone excitation) and blue (S cone excitation) we can replicate in the eye the cone response any visible colour would generate.

The human vision system is not like a camera - the cone response is only one part of a long and complex chain. Afterimages are somewhat a function of photo-pigment bleaching and later stages of visual processing in the nervous system and brain.

Cone response references:
Stockman, A. & Sharpe, L., "The spectral sensitivities of the middle- and long-wavelength-sensitive cone derived from measurements in observers of known genotype'', Vision Research, Volume 40, Issue 13, Pages 1711-1737, 16 June 2000

Re:Great Blazing Colors ( Score: 5, Funny)

A slashdot post citing references?

You, my friend, are way out of line.

Re:Great Blazing Colors ( Score: 5, Informative)

Good writeup. Found a simplified reference with a picture. I'm visual, don't you know-)

In terms of raw sensitivity, green produces the most signal at the lowest intensity. I've personally found that is true, and green on black is my usual choice I've tried them all, yellow is next best, which also fits the curve.

As PP points out, though, the visual system is complex, and the receptor distribution will vary for each person. It's also been found (no reference, sorry) that most people read words as a chunk, not by resolving and assembling the individual letters, so choice of font and kerning probably has more to do with readability than the color of the text.

Re: ( Score: 3, Informative)

Wikipedia [wikipedia.org] has a good article describing this and the fact that our eyes are actually sensitive to blue, green and greenish/yellow. Red is what you see when the greenish yellow receptor is active but not the green, hence why we aren't all that sensitive to red light but very sensitive to yellow and green. Similarly if only the blue receptor is active you see a deep violet like what you get from a black light.

As far as monitors go, it's often easier on the eyes if you lower the color temperature to 6500K.

Re:Great Blazing Colors ( Score: 5, Interesting)

Yeah. That's also why unless you are colorblind, light yellow on a very dark blue will probably be about as readable as it gets because it has both luma contrast (difference in rod response) and chroma contrast (the yellow hits the red and green cones hard with just a little on the blue cones, the blue hits the blue cones and barely registers on the others). Even if you're colorblind, the huge difference in contrast should be sufficient to make it reasonably readable.

The absolute worst, IMHO, is white on medium green. you know. road sign colors. Unreadable until you get right up to the things, by which time you end up cutting off the guy in the next lane to slam your car into the exit lane that should have been marked 200 feet earlier. -D

Re:Great Blazing Colors ( Score: 5, Insightful)

A lot of cities have started installing new road signs that are white on blue, or even a faint yellow on blue. They're also making the text paint reflective, but not the background blue. Unfortunately, the cost of replacing all the road signs is prohibitively expensive, but at least new ones going up are a lot easier to read.

I still wish someone would start requiring road signs to be sized appropriately for the speed of the roads. Speed limit signs are required to be larger in places where drivers go faster to give them additional distance (time) to be able to recognize the sign. Road signes need to do the same.

Additionally, we should have cross street hanging signs (the big ones hanging from traffic light wires) on every block in cities. Here in my city, it's hit and miss, some streets have them, others don't. if I'm in the left lane, there's little hope I can read a street sign, even when parked at a light. It's simply too far away to read 3" tall letters. especially on green backing.

Re:Great Blazing Colors ( Score: 5, Informative)

Re:Great Blazing Colors ( Score: 5, Informative)

Our eyes don't work like that -- they don't scan the visible spectrum from low to high, and see blue as the opposite end of red. Instead, we have receptors for certain colours, and base our colour perception on how much each of those get triggered. This is why colour blindness hits red/green or yellow/blue, despite those colours not being adjacent on the spectrum.

Yes, we have different color sensors, but this is beside the GP's point. The green response curve overlaps significantly with red and blue. See the spectral response here [ed.ac.uk]. Red/Blue flashing lights will cause a significant color contrast as they alternately hit one type of cone and then the other. Even though the response to blue is low, it is still an effective color to use because the human eye's response is logarithmic wrt to brightness (i.e. take the graph I linked above and take the log the y dimension). Even that's a simplification when you add rods to the mix, but that's a subject for another post or later research.

Our eyes can differentiate shades and hues of green better than any other colours -- this is an inherited survival trait from when it was important to see predators and distinguish ripe from almost-ripe. Blue, on the other hand, wasn't as important to survival, so we can't tell too many shades of blue apart, nor very far towards ultraviolet.

This is wrong. We can identify more hues of blue than any other color, followed by red, while the intermediate hue discrimination can be quite low. Green sucks because that cone's frequency response is highly correlated with parts of the other two, and thus it forms somewhat of a degenerate basis for describing a hue with the 3 weights. Google "Hue-discrimination curve" for more info.

The evolutionary argument for this has *no* good evidence supporting it, but has become a very vibrant meme (I won't call it a legend, since it is an unproven theory). Green is bright for a variety of potential reasons: (1) It's one of the easier pigments for synthesize biologically, (2) There's a lot of green light coming from the sun, (3) It's a good baseline from which to differentiate other colors (there's a lot of green in our environment), and (4) yeah maybe it could have to do with rotten/ripe fruit. I'd bank on the first two though, especially noting that our hue sensitivity in the green range sucks. Predators are best to detect via motion (primarily rods), and by non-green cones (predators are camouflaged best against rods, i.e. non color vision, i.e. luminance, which overlaps most with green). You can of course believe whatever theory you want, but please don't start speaking about one as being authoritatively true I know some evolutionary biologists like to extrapolate really far from the evidence, but it always hurts when they are wrong on some theory that gets discounted, since it gives creationists a hammer to bludgeon all of biology and science with. Please don't give them that ammo, and label speculation as speculation until there's real concrete evidence to show. For evolution of these traits, that means sticking mostly to the "what" and "how", and not claiming "why" except in the most general and statistically supportable terms.

We perceive indigo (the traditional indigo, not the "purple" that's called indigo these days) as a dark colour, for example, because it's at the edge of what we can see.

It's not just that its near the edge, it's more complicated with several factors: (1) The blue cones are not that sensitive, (2) there is no additive luminance response due to the other cones frequency response falling off completely at violet, and (3) the rods don't even respond to it very well (last point only really matters for

Re: ( Score: 3, Insightful)

Re: ( Score: 3)

Re:Great Blazing Colors ( Score: 4, Interesting)

Red, being the longest wavelength of visible light (that lines up with a color receptor), carries farther especially in foggy, snowy, rainy, or other inclement conditions. This is why stop lights, stop signs, and tail lights are all red.

Blue, being the shortest wavelength of visible light (that lines up with a color receptor), is seen more vividly and in greater detail than other colors. "Ultra white" paper is actually tinted blue because of this, and many whitening laundry soaps are reactive on ultraviolet (which tickles the blue receptors without being visibly blue).

If you use a color calibration sensor, such as professional printers use, you will find that paper which is truly white in the scientific sense (equal strength responsiveness across the spectrum) seems kind of yellowish and bland compared to this ultra white stuff with it's big blue and ultraviolet spike.

I think this is why police lights are red and blue, red to carry in inclement conditions, blue to get your attention.

Re:Leopard OSX fonts a polychromatic and easy to r ( Score: 4, Informative)

Re:Leopard OSX fonts a polychromatic and easy to r ( Score: 5, Informative)

CRT pixels do not line up precisely with their r, g, and b light emission points, at least on most CRTs. If you look at a single white pixel on a field of black through a lupe, you'll see it's composed of a number of red, green, and blue dots, not one dot for each color. Look at a different pixel, and the exact pattern will be different (shifted a little).

They use a couple of electromagnetic coils in the rear of the tube to guide an electron beam to the right point on the CRT's surface, but it is not so precise on most models (though maybe some really high end stuff for scientific work) as to be able to exactly hit specific phosphorescent spots.

This is why sub-pixel rendering works on LCDs but not CRTs (which turn on and off [or shade] specific color points digitally), because we know the exact shape and color layout of each pixel.

Re:Leopard OSX fonts a polychromatic and easy to r ( Score: 5, Informative)

If you read the follow up you'll see that that is not a feature of Leopard, but the result of sub-pixel rendering. It's a technique for making text look better on LCDs.

Steve Gibson has an interesting article on it here:

Re:Leopard OSX fonts a polychromatic and easy to r ( Score: 3, Interesting)

Re: ( Score: 3, Informative)

Sub-pixel antialiasing might look sharper, but it'll always feel a bit out of place. I don't think it's easier to read. If you want bolder fonts, make them bolder, it's just that simple. If anything, sub-pixel precision is going to make them thinner.

On Windows font antialiasing makes fonts thinner but not on a Mac. On a Mac their goal is precision of the characters for print so the sizes and thinkness are correct although they look a little fuzzy on screen.

Re: ( Score: 3, Informative)

Re:Great Blazing Colors ( Score: 5, Insightful)

Green on black terminal windows are the way they are for the same reason old oscilloscopes and radar displays were green on black - it's more cost effective to make a cathode ray tube that glows green. For a long damn time, all terminals came green-on-black, simply because that was the cheapest way to pair a CRT with a keyboard, and hardware terminals were what they used back before PC's were popular. Or invented.

The result of this was horrific eyestrain. Yes, some people can handle bright colored text on a black background. Most get eyestrain or worse, migraines. This is especially so if you switch from green-on-black to black-on-white (like a printed page).

Typists and transcriptionists and grad students and pretty much anyone who needed to refer to a printed reference hated it. In the early '80s, color monitors were pretty much crap for text (too fuzzy, not enough resolution) so there was a boom in the production of "amber" monitors. These used monochrome CRTs that phosphoresced a muted yellow-orange. This wasn't quite as jarring to the eyes.

Then someone came up with paper-white monochrome CRT's, and that was pretty much all she wrote for greenscreens.

Geeks keep it alive, because of nostalgia and tradition. It's looks high-tech and cool, because there was a time when it was high-tech and cool - and because there is an association with Unix, and by extension, Linux. What's more Unix than a DEC vt100 terminal hooked up to a PDP-11? Nothing. That's about as close to the metal as you can get without a soldering iron.

But, please, for the sake of your eyes and the eyes of others, don't pretend there is any inherent advantage to green-on-black for the vast majority of users.

Re: ( Score: 3, Interesting)

Bullshit.
Double bullshit.

First, what is more tiring, some glow, when most of the retina remains inactive picking 'dark', or a full blast from a CRT tube against your eyes?
There are these who prefer bright background with dark letters over the opposite, but I assure you you'll find few of these amongst CRT screen users, and the choice of white on black for office applications was to make it all resemble paper, the old known metaphor for 'surface for writing'. Not because it's easier on eyes.

Re: ( Score: 3, Interesting)

The result of this was horrific eyestrain. Yes, some people can handle bright colored text on a black background. Most get eyestrain or worse, migraines. This is especially so if you switch from green-on-black to black-on-white (like a printed page).

And it never occurred to you that this might be the fault of the colour scheme these people were switching to? I always have to turn down my brightness and contrast settings as low as possible to be even able to read Slashdot for more than a few minutes.

Re: ( Score: 3, Interesting)

Honestly, what a load of hogwash.

Green-on-black is perhaps the nicest thing to my eyes ever, though I am partial to Amber-on-black.

White on black hurts after a while. Black on White hurts more - I have a *MUCH* lower tolerance working with an IDE with a white paper colour than a black one. Of course, being a proper programmer, I use vi from a shell:)

Yes I actually used serial terminals for years, usually in the higher column mode - just because I could read more:)

I kinda miss hacking on the old CP/M bo

Re:Great Blazing Colors ( Score: 5, Interesting)

The retina doesn't get tired. it doesn't move.

The rest of the eye does as it tries to focus and refocus on a dark-but-not-dark environment, and the iris goes between contracting and expanding because it can't get a read whether it should be letting in more light because the background is too dark or contracting because the letters glow too bright, and the part of the brain running the ocular show will often make its displeasure felt in the form of splitting headaches.

For similar reasons, white text on a black background, while not as bad, isn't exactly good. This is why legal pads are pale yellow, and ledgers are pale green. Contrast is good, but too much contrast hurts.

Re:Great Blazing Colors ( Score: 5, Insightful)

"The retina doesn't get tired. it doesn't move."

Don't be pedantic. Tired doesn't just refer to muscle fatigue and retinas do indeed become less responsive without rest.

Re: ( Score: 3, Interesting)

I know a lot of geeks like dark working environments. However, it is well established that this is bad for your eyes in the

Personally I found that ( Score: 5, Informative)

. if black on white hurts your eyes, there's probably something else wrong there too. Not saying that black on white is optimal anyway, but it shouldn't be enough by itself to give you a headache or tire your eyes.

It generally boils down to: IMHO most people I've seen using computers are doing it wrong for their eyes.

For starters make sure you use a large enough, and clear enough, font so you don't have to squint. If you absolutely need 80 lines on the screen when editing sources, that's usually your clue that there's something wrong with your programming style (and I suspect for some people the short term memory too.) You shouldn't have methods that run over that many lines, unless they're truly trivial stuff. (Like, say, a long switch statement where each line does no more than delegate to a method of its own. Arguably there are better ways there too, but I don't find it to be the end of the world either.)

IDE's also offer a lot of tools to find the method you need, when you need it, and/or collaps/expand blocks so the don't take up screen estate when you don't need them. There's also stuff like showing you the parameters anyway, so you don't have to have a second window in which you look for the parameters to that method. And really lots of other stuff. Use those instead of cramming the absolute maximum lines of text on the screen.

When I see a couple of co-workers squinting at their 6 point Illegible Roman font in VI and doing greps manually in another illegible tiled window, heh, I'm just itching to tell them to move out of the stone age already. We even discovered this funky thing called the "wheel" in the meantime, ya know?

Clean your monitor regularly, especially if it's a CRT. CRT's have thick glass, and your eyes end up focusing back and forth between the dirt on the front side of it, and the letters on the back side of it. But it's distracting and tiresome on TFTs too. And if you need to squint because you're at the point of "is that a 'm' or a 'rn'? Or is it 'rh' behind that speck?" it's long overdue for a cleaning.

Do turn your contrast up, but turn your brightness down to a comfortable level. The monitor is not supposed to be an AA searchlight. Staring into very bright stuff, especially in a dark room, _is_ tiresome. Here especially the TFT's are the biggest offenders. The manufacturers got stuck on bragging about the brightness of their monitors, as if that's something good, and pre-set them to insanely bright levels. Turn that down to where you can live with the white for hours.

And it will be even more important when you have to focus on stuff that's the other way around: white on black. (Some websites love that scheme, for example.) On an ultra-bright monitors that will mean focusing on a mostly black screen, so your pupils are wide open, but some pieces of retina are getting to see some really bright letters. It's a recipe for a headache.

As a side-note, I'm genuinely surprised at how many people do the exact opposite. I've seen too many monitors which are turned to abysmal contrast, and as bright as halogen headlights. I mean, WTF? Some things are barely legible in that configuration.

Ok, so maybe it's good for PC games, where the average dev seems to think that every fucking thing must happen in nearly complete darkness. 'Cause, you know, we have 32 bit colours so we can display all the gamut of "black", "really dark", "dark grey", "room with a broken lightbulb" and "grey stone on a moonless night". But the brightness settings where you see in near dark in games, suck for work or even reading in a browser. If you use the same monitor for games, consider turning up the brightness or gamma up in those, instead of turning the monitor's brightness all the way to the right.

If you're stuck with a CRT, make sure it's a good one and properly tuned. Staring into an unfocused image, especially with small unfocused fonts, is a recipe for a headache.

Again, for CRT users, just because everything idiotically defaults to 60 Hz, is no

Re:Great Blazing Colors ( Score: 4, Interesting)

I usually use a dark grey on a medium or dark grey. Maybe something like #222222 on #777777. Enough contrast to read easily, easy on the eyes, and easy to focus on something else quickly.

White on black makes my eyes bleed, especially when trying to refocus quickly off-screen.

Re: ( Score: 3, Interesting)

Re: ( Score: 3, Interesting)

I'm also used to green on black. And green is better than yellow or white on CRT monitors which have convergence problems, because you don't have red and blue that need to converge to green. It's probably better even on LCD monitors when you need small fonts. Also, out of the three primary colors, green appears the brightest (human eye perceiving).

Anyway, I seem to be very confortable with black on white used by web browsers if no convergence problems exist (no old CRT).

In fact, given a good LCD monitor, black on white should be the best.
cleartype (or whatever subpixel rendering is named in your platform) is very good for providing nice easy to read letters. Full color works better with that rendering, so black on white whould be the best. Contrast should be high, and brightness should be adjusted to the lighting of the room. More light, more brightness.

The more it can look like paper, the better. Paper works great.

Re:Great Blazing Colors ( Score: 5, Insightful)

Because the screen directly emits light, it is typically more tiring to your eyes. That's why people often prefer light text on dark background for a screen. I generally choose "old school" green or amber on black.

Re: ( Score: 3, Interesting)

Re:Great Blazing Colors ( Score: 4, Informative)

I thought military used red on black so you don't lose your night eyes.

red on black is NOT easy on the eyes, as anyone who's owned a virtual boy can tell you.

Re:Great Blazing Colors ( Score: 5, Interesting)

Re: ( Score: 3, Interesting)

Eye-friendly color combination ( Score: 5, Funny)

Re: ( Score: 3, Funny)

Re: ( Score: 2, Funny)

Re: ( Score: 3, Interesting)

White on white ( Score: 5, Funny)

I am and because of that ( Score: 5, Funny)

Re:But that's still not as funny as. ( Score: 5, Funny)

Colour? ( Score: 5, Insightful)

When you work with computers for long periods of time, the colour of the font is nothing compared with taking regular breaks. Look out the window. Go for a walk. Make some tea. Bump up the font size. Get a bigger monitor and put it further away.

You are focusing on a tiny, tiny, tiny piece of the problem. There are almost certainly a ton of ways in which you could reduce eyestrain by gigantic amounts in comparison without bothering with something as trivial as font colour.

Correct, also calibration and slashdot circa '01 ( Score: 3, Informative)

You gotta explain for us Americans. ( Score: 5, Funny)

Re:Refresh Rate ( Score: 5, Interesting)

indeed. it's insane how many CRT monitors are still operating at 60Hz when almost ALL of the hardware being used today is capable of higher rates.
For some of us with sensitive vision, looking at a 60Hz screen is like reading text written on a strobe light. Even if it doesn't subjectively bother you, it does cause increased eye strain. Apparently even OSHA cautions against 60Hz.
A good document on this issue ( show it to your librarian, IT pro, or whoever has locked you out of the control panel) is available here: http://www.nhpa.org/docs/ComputerMonitorFlicker.doc [nhpa.org]

Re: ( Score: 3, Informative)

Re:Refresh Rate ( Score: 4, Insightful)

It is probably true for those very old monochrome monitors that had like half a second of persistence, but it is definately not the case for color TVs. Yes, there is some persistency, but over 95% of the photons are emitted within a millisecond after the electron beam hits the phosphor, and the other 5% are emitted gradually over tens of milliseconds. The net effect is that there's sharp flashing, plus about 5% (in this example) of a more-or-less constant background. That is not going to improve the flicker a lot otherwise you could just point a lightbulb at your TV to increase the background illumination.

You can see the background light for yourself by taking a photo of a TV screen with a 1/200 exposure time.

What makes the flicker less obvious with a TV is that you normally watch a TV at 5-10 times the screen diagonal, and a computer monitor at only 2 times the screen diagonal, such that a much larger area of your field of view is covered by the screen. People are most sensitive to flicker at the edges of the field of view.

Re:mod parent up ( Score: 5, Funny)

Easiest ( Score: 5, Funny)

Re:Easiest ( Score: 5, Funny)

#000000 ( Score: 3, Insightful)

Black background font in black.

You know what? Just turn the monitor off and go look at something with depth-of-field.

Not color ( Score: 5, Interesting)

Re: ( Score: 3, Informative)

Seconded. Monitor at 50-60% bright, color temp at D50. Give your eyes a while to adjust (as in, give the cramps a while to subside), maybe a day or two.

I've still got my decent CRT from. 1998? 1998. Black-on-white for documents, green-on-black 10pt Courier for terminals, syntax coloring is ok mostly. I miss the layout tweaking I could do on Apple's Terminal line- and letterspacing with sliders let me get my setup Just Exactly Right. It matters.

Why, Pink of course ( Score: 5, Interesting)

Another webpage that makes effective use of colors ( Score: 3, Funny)

Green or Yellow on Black ( Score: 2, Informative)

A little more info please. ( Score: 3, Interesting)

There are so many variables to this.

  1. What medium are we referring to? CRT monitor, LCD monitor, printed matt page, Hi-gloss paper?
  2. How much ambient light is there?
  3. What type of ambient light is there? Incandescent, fluorescent, halogen.
  4. What is 'a long time'?
  5. Who are we talking about? A 7 year old child, a 30 year old office worker, a 50 year old proof reader.

Re:A little more info please. ( Score: 5, Informative)

If you are in a dark room, anything with a white background is waaay too bright, and light color on dark is preferrable. In a bright environment, on the other hand, the you see more reflections against a dark background, so you want to make your background bright, and the font color dark.

Easy answer ( Score: 2, Funny)

Don't you mean what colors? ( Score: 2, Troll)

Bright BLUE on vibrant RED . ( Score: 5, Funny)

Clarification needed ( Score: 3, Insightful)

What is "best" will clearly depend upon what criteria you consider. Are you talking about a combination that is teh least likely to lead to damage to the eyes, the combination which causes least pain while reading, or the combination that is most comfortable? Does psychological factors count? Is your userbase young, old, mixed? I would imagine the answer could differ depending on these cases.

The only thing I can tell for certain is that the claim that looking at black on white text on a screen is like starring into a light bulb is complete nonsense, and it is very easily confirmed that the two are nowhere near the same by simply looking into a light bulb ( thou it is probably best to limit such experiments in order not to damage your eyes ). While your pupils can somewhat adjust for the incoming light, starring into a light bulb at short distance will almost certainly overwhelm your eyes with light, while looking at the computer screen does not.

The fact that a computer screen emits light does not in itself mean it will be "brighter" than a paper. It can as an example be very difficult to read some LCD screens outdoors because the relatively faint light they emit is completely drowned by bright sunlight reflected off it's surface. Now, while it may or may not be true that it is "not good" to have all light coming from only one place in front of you (which would appears to suggest having a lit computer screen in a dark room is bad ), this could be easily avoided by simply adjusting the surrounding illumination and screen brightness, and I find it very doubtful that there is much a web designer can do to optimise his webpage for every single situation since users will change the brightness and contrast of their monitors.

As a pure guess, I would imagine that weather your color scheme is familiar, if your font is large enough, and the reader's "taste" has a much greater impact than most physiological effects, and thus I would recommend a black on white color scheme with a clear simple font of sufficient size. Most people find it acceptable, and there is as far as I know little evidence that it should be troublesome.

A serious response. ( Score: 5, Interesting)

Re:a serious response. ( Score: 4, Insightful)

Actually, the problem is, people don't use light-on-dark properly, which makes it even harder on the eyes. If you use a thin font like Heveltica or Arial, white-on-black causes the letters to turn into a light grey. The thing is, the black "creeps" onto the lighter color. The general hints have been to either use bold, which fattens the letters enough to offset some of the creep, make the font size larger, or choose a fatter font. All of this helps offset the creep - it's only at the larger sizes does the effect of the creep become less noticeable. It's why I hate when Courier is used as a default font - it's damn hard to read on a black background. On Windows boxes, I much prefer the fat and easily read FixedSys.

But there are tons of contrasty color combinations. White-black is generic and isn't eyecatching, but great for long sessions. Colors like Yellow-on-Blue are easily read, and the blue doesn't actually "creep" into the yellow too badly. Yellow-Red and Yellow-Green work well too. But yellow can be quite tiring to read.

Re: ( Score: 3, Informative)

Actually we see yellow, green and blue. We perceive red by the yellow cone being active in the absense of green. Pure blue appears as a deep violet (i.e. a blacklight). Some women have two different yellow receptors (which are on the X chromosome) and there is some variance between people for yellow.

Depends on the environmental light ( Score: 2, Interesting)

For different working environment, e.g. with different "general background" color/brightness, you may need different color combination.

Well, nothing could prevent the eyes' fatigue if you keep on looking at the screen too long.

Well at least we're all on the same page ( Score: 4, Interesting)

. because none of us have RTFA - as there isn't one.

Err, that's nice. Where's the links?

I prefer black on light gray ( Score: 2)

Answer: Whatever makes you feel the best ( Score: 5, Interesting)

I'll chime in as a physician.

I always wondered in medical school what causes eyestrain -- your mom probably told you "don't read in poor light," but since the photons are easily sufficient to give an image on your retina, this didn't make sense to me.

It turns out that your eye muscles have a difficult time obtaining a rapid and precise focus with poor light, which gives less contrasts on the edges that are detected for sharp focus. In low light conditions, the eye muscles are rapidly focusing back and forth, and these micro-contractions can fatigue them similar to the other large muscles of your body. As an analogy, imagine walking on level ground versus on a balance beam. You are constantly contracting different adjustment muscles to walk on a balance beam, using more energy and promoting fatigue.

So, in answer to your question, you would want a high-contrast color scheme to make it easy for your eyes to focus on the letters. "Duh," I hear you say.

Next, I would recommend minimizing the difference in brightness between your monitor and the outside environment and its background. That is, in a dark office have a dark monitor, and in a bright office, a bright one. Why? Well, same reason -- your eye muscles have to dilate your pupil every time you look away from a bright monitor to a dark monitor. More contractions / adjustments -> more fatigue. Not only that, but the high brightness contrast will give ineffective normalization of light across the eye receptors and could cause headache.

Regarding your study question -- difficult to fund, and difficult to accomplish. I guess you would have to divide several hundred office workers, and try to have them work the same hours under same conditions with different fonts, and then ask a subjective question regarding symptoms. It could be done, but I am not sure of any well-performed efforts that have addressed this question.

In summary, I would just choose contrasting colors that you like or find subjectively pleasing, and then keep the brightness on your monitor appropriate for ambient lighting. Also, don't forget to focus on the numerous other ergonomic factors on your workstation. I see a *lot* of people with bad backs from the workplace, but there are a lot of 80 year old secretaries that are not blind.

Cue the contempt for expertise from the anti-intellectual crowd now.:p

Re:Answer: Whatever makes you feel the best ( Score: 4, Funny)

You are on the right track but there is more ( Score: 5, Interesting)

You are on the right track but there is more. Yes, higher contrast is better than lower contrast. But how this works with color is complicated.

One big issue is that the eye is not perfect optically. It cannot focus all colors at the same focal plane. Just how well it does varies by individual and the optical conditions of their eyes, and the quality of corrective lenses (which usually make it worse with respect to the ability to simultaneously focus all colors).

An important factor to consider here is which color or colors the difference is at the edge being focused on. For example in the "hot dog" pattern that has been mentioned in a reply here, the difference is actually in green. If the red level of the yellow part is exactly the same as the level of the pure red part, then all the difference is in green and this is an issue of green contrast. Yellow on red like this is essentially the same as green on black. except that the extra red light with yellow on red causes the iris to close down more than the darker green on black would.

I find blue to be the worst to focus with. That may be because my sources of blue light are not sufficiently narrow band in the spectrum. Being spread out over the spectrum, it basically comes in fuzzy. Blue is also lower in contrast.

Green (be it green on black or yellow on red or even cyan on blue) is better.

Red seems to be the best in terms of focusing a sharp defining edge. You get red contrast with red on black or yellow on green or magenta on blue.

Unfortunately, effective contrast goes down when extra light is added in other colors. So you have to find a balance trading off the sharpness of the edge vs. the contrast. I've found a good compromise in orange on dark green (the level of green in the orange is the same value as the green background). Think of the orange in a neon sign on the green felt of a pool table. Then when I need to highlight something, I shift over to pink on cyan. basically add the same level of some blue to both the orange and the dark green.

A related issue is light quality when reading a book or newspaper. Usually we are stuck with black letters on white paper. The consideration is then what type of light. I find that incandescent light, or sunlight, works nearly best for me for long term reading. Fluorescent lighting is worse. Ironically, I find high pressure sodium vapor light is about as good as, and sometimes somewhat better than, incandescent light.

To understand this, look at the spectrum. Incandescent light has a fairly even level through all light wavelengths. This makes those black on white edges a bit fuzzy. But fluorescent light has two narrowband peaks at a red and green wavelength (the blue is broader). This can make the text edge sharper. twice. The eye ends up with two contrast edges. I believe this increases the eyestrain by causing the focus to be constantly jumping in and out to alternate the focus on the two different edges. It's a very small adjustment, but it is there at least for me. With incandescent light, it just settles in the middle of the fuzzy range and doesn't change much. And this is affected by how much light there is, which dictates how small the iris becomes. Higher light levels with a smaller iris won't change the effect from fluorescent as much as for incandescent, since with fluorescent the two contrast edges are already rather sharp due to the two narrowband spectral peaks. But for incandescent, the high light level helps (up to the point that intensity is too stressful).

This is why I believe we still need to keep some incandescent lighting around for reading and other close/fine work for long periods of time. I get a headache when working on things I need to look at closely when doing so under fluorescent light. The onset is about 25 to 45 minutes. I don't get the headaches under incandescent. And I have verified that the flicker is not the cause. White LEDs


What is the most readable screen font? - Psychology

Is it better when making a presentation with a Proxima(tm) type projector to use light/white text with a dark background or dark text with a light/white background?

The usual metaphor for screens (projection and computer) these days seems to be black type on a white background, that is, a paper metaphor. This sometimes results in video glare, with lots of rays coming from the background. Sometimes the old fashioned computer screen seems less tiring, showing lit-up text on a dead backround.

So you should try to reduce video glare, perhaps by reducing the figure/ground contrast. For example, our screens on this website usually have a light tint on the ground to reduce the electric blue-white video glare. Of course on the computer screen, one can just turn down the brightness control when working at night or in a darkened room. Television control rooms and airplane cockpits generally have darkened backgrounds upon which to display lighted data.

On paper, white type on a black background can result in filled-in serifs because of the printing process. It is also harder to read white type on a black ground (there surely must be some evidence about this). But we should never be working at the edge of legibility in any situation, so legibility tests might not be relevant.

For projection presentations, obviously the figure/ground contrast must be sufficient to overcome the ambient light. Check your presentation room out in advance, test your projectors, find out how to control the room lighting and the window curtains if necessary. You should simply look at the various design solutions under real conditions to see what is going on, and not depend on verbal discussions such as this to decide!

I frequently use white text on a black background, because it removes the "frame" around the image or text being shown. The frame conveys no information.

Further, the frame limits where things can be placed on the slide. Because we are used to margins in printed text, we expect some space between images / text and the projected frame (the paper metaphor E.T. referred to). By using a black background to remove the frame, an image can be made larger and thus more visible. This is particularly helpful if the image does not have the same proportions as standard slides (i.e., 2:3 for film slides 3:4 for computer screens, PowerPoint).

Other advantages to projecting white letters on a black background rather than vice versa:

Another good reason to have dark backgrounds and light lettering on PowerPoint slides is because of an optical illusion. Try this. Compare two shapes, say circles, of the same size, one white with a black background and one black against white. White against black always appears larger than black against white.

Hence, across America we see interstate highway signs with a dark green field and white lettering that "glows" when illunimated at night. In Beijing, China, where I teach, the street signs are dark blue with white lettering.

I recall an undergrad Psychology course from about 1971 in which the text authors claimed research showed black text on yellow paper was best for readability (comprehension?). The text used exactly that scheme: black text on yellow paper. Anyone else aware of this research? I have no idea who the authors were.

There is a great study from Stephen F. Austin State University in Texas on readability on the web. Read a summary here, or on Wikipedia.

Are there any different suggestions for longer term exposure to projected presentations? For example, every day for three weeks if you are on a training course. Should we change the colour every day to keep them interested? Should we change it for the period just after lunch when they become lethargic? Should it change to reflect the content or how they learn?

I am involved with the production of training courseware for military end users. As these courses are entirely computer based, the students may spend all day in front of the projector. The environment is controlled (lighting and such like) and standardised. We have followed the paper paradigm with black text on a white background for a number of reasons.

Primarily, because it is visually uncluttered (title, graphic, text). You have total continuity between screen and paper (we also have to produce the manuals to go alongside the presentations) which this also keeps printing costs down. It's quite a spartan approach (no watermarks, no background).

Can I make a plea for people to remember that not everybody has perfect eyesight. In my work I get involved in public talks to groups of all ages (literally from babes to 100 year olds) the fancy background so loved by many of the presenters at these events are not suitable for older members of the audience. And that's before one considers issues such as colour blindness.

In addition to the links given earlier for colour studies I use Vischeck to show me what pages will look like to those with colour blindness problems. There is a option there to test your own web page(s). Worth the effort. Not everybody has perfect eyesight like you.

I think that inclusive design has started to become more mainstream thinking recently, in many areas of design. The huge (in the UK) DIY company B+Q have a range of powertools designed to inlcude those with limited hand mobility (i.e arthritis). These are well designed regardless of the inclusivity brief and stand apart aesthetically and functionally (i.e. an electric screwdriver that you squeeze to operate). Inclusivity can lead to new ways of thinking and solving problems.

The RNIB (Royal National Institute for the Blind) launched guidelines for inclusive design for print. I am not sure how widely this has been used but it would be interesting to find out how this could lead current layout styles (small text vs big text).

Being partially colour blind myself, I tend to stick to black, white, red, green, blue, cyan, magenta and yellow. I also try and memorise colour codes of successful colours as looking at a colour gamut chart in photoshop is a no-go!

The recommendation for limiting eye strain on VDUs is to make the screen background a similar shade to the surroundings. For a projected image, then, a black background is preferable because it is exactly the same shade as the surroundings.

I use Trebuchet font, coloured 'ivory' (not white) on a plain black background. White text is good for subtle highlighting. The text goes right to the edge of the slide, but since the background is black, who misses the margin?

Everyone here seems to prefer light type on a dark background. There are reasons to disagree. Most typefaces including screen fonts are designed for black-on-white. Second, many talks are given under conditions where the presenter will have no control over lighting. White backgrounds ensure that there will be at least some light in the room. Third, in my own experience at scientific meetings, where one sees a weeklong succession of 15-20 minute talks, each prepared by a different person, the light type-on dark slides are *not* easier to read, and screen glare is a hypothetical, not actual problem.

One presenter points out that the background for a VDT should be close to the luminance of the VDT. At least for scientific talks, the object of interest very often ends up being a black-on-white data graphic embedded on the slide. A black slide background often contrasts brutally with the embedded data panels, and makes such figures much harder to resolve. A great deal depends on the specific slide layout and typography, but the hypothesized advantage suggested by many here does not, in my experience, exist.

Finally, the darker the room is, the easier it is to sleep, and the harder it is to make notes.

Regarding the matter of sleepiness:

From Tortora & Gabowski's Principles of Anatomy and Physiology, eighth edition:

Light = wakefulness is a double-edged sword. I meet many struggling college students in my job and the most common problem is sleep. I suspect spending too much time in front of a bright VDT late at night has something to do with this.

Use white backgrounds and keep the lights up in presentations. Send your kids to school with laptops, not desktops: at least they can close the screens.

Niels's post raises another reason why white backgrounds are preferable in presentations. Several optical aberrations are more severe in large-aperture systems compared to small- aperture systems of the same focal length. This is why most camera lenses have less contrast and resolution when used at full aperture (e.g., f/2) than when the aperture is closed (e.g., f/8). The same is true of the eye, which is why it is often possible for a person with myopia or astigmatism to read small print by squinting.

In dimmer light, the eye's aperture - the pupil - opens, and optical defects increase in severity. Hence as our vision deteriorates with age, we need brighter light to read by. The lesson for presentations seems obvious: dark backgrounds will result in dilated pupils and poorer vision. This effect should be worse for people with worse eyesight. At least that's the prediction. Quantitative tests of this notion would be straightforward and useful.

I give many presentations, lectures and trainings in a variety of settings, often to audiences diverse in age, ability, language comprehension, etc. I agree that the best choice is what works best in each individual location. However, it is a luxury to have that much time, information and control over the situation.

Using dark text on light backgrounds has almost always been the best choice for me. This is especially true when photocopies of the presentation are required and when other visual props and devices are also used.

The aberrations of the wide-pupil eye are the reason I switched from using white on black screens to black on white, even back in the days of DOS text screens. In addition, the white background "blooms" into the black letters, giving an impression of finer type and on graphs, finer lines. White on black letters seem bloated, by contrast.

However, nowadays I find that a pure white background is a bit harsh. I have set my Windows pallettes to emulate this website -- Tufte's ivory white.

A retired heart surgeon with many years of medical experience approached me with some wisdom about the color of projected backgrounds. He said that the light receptors (rod and cone cells) in the eyes of young and old alike are strained and become tired when forced to look at a brilliant white projected image in a very dark room environment. His advice was to do the following:

1. In venues where the room environment is dark, a stark white projected background creates a stronger more straining and single point of focus for our eyes. Therefore less strain on our eyes would be caused if the background were darker and the text lighter. I found this to be true.

2. On a computer screen in an environment where the general lighting conditions around your monitor are illuminated, the background color best serves the viewer with less strain on the eye by being a lighter color or value with the text being darker.

My observations over the last twenty years of designing and producing presentation visuals for projection, print, and computer are centered in three principles:

1. Design for the audience and the environment.

2. Make it as easy as possible for the audience to get the message.

3. Use a pallete of comfortable color contrasts that work to decrease eye strain.

For a long time I used a text editing program on the mac (intended mainly for programmers I think) that had a button to toggle between "day mode" and "night mode". You could customize the colors for each, but the idea was that "day mode" was dark-on-light and "night mode" was light-on-dark. I didn't always use this feature but it was nice to be able to quickly switch if I didn't like one or the other.

As a frequent presenter I've resolved this question for myself as, "It depends," finding that dark text / light background serves best in well-lit rooms, and light text / dark background serves best in darker rooms. For particularly important presentations when I do not have control of the lighting or can't predict what I'll find when I arrive, I will prepare two versions of a presentation, one light / dark and one dark / light, and use whichever best serves the context.

I also use a non-standard screen size -- a golden rectangle -- for my presentations. I do so to make certain projected images and slide layouts more visually compelling, but it only works with light backgrounds or with full-bleed images when the frame is obvious. Of course, with full-bleed images the question of background color ceases to be a question. With text rich slides (which I do not as a rule use) I would heed the counsel of other posters and go dark background to do away with the margin.

Finally, I might respectfully suggest that if we are too concerned with the readability of our text on-screen, or that eye strain may become an issue, this is a signal that the information is better served by a printed handout than an on-screen display. If there's one thing I took from ET's Cognitive Style of PowerPoint essay, it was (my paraphrase): "Pictures on screens, words on paper, unless the words serve as pictures."

Much of my work involves PowerPoint, and I've done a lot of work for companies presenting to government agencies. Usually, these meetings are held in hotel ballrooms, where the ambient light desaturates even the most colorful slides. After being asked to "brighten the slides", my attempts to satisfy the client by using the most saturated dark blue (R0, G0, B255) and by attempting to "brighten" the other colors still failed. Attempts to generate constrast by means of color were also unsatisfactory.

I attempted to solve this problem by using a strip of dark blue for the title area (R0, G0, B204) and by using plain white for the content area, but plain white introduces other limitations. For example, the apparent contrast of cyan (R0, G255, B255) on the dark blue mentioned above is quite different on plain white, when projected.

Consideration must be given to the relative luminance of the color choices. A green line (R0, G255, B0) and a red line (R255, G0, B0), when laid on a white field and projected in a venue with high ambient light, will appear surprisingly similar. When laid on a dark background, the differences are more apparent.

Digital projectors technically can project 16 million colors, however, in practical terms, the useful color range is much more limited. In conditions with high ambient light, background colors that use RGB values below a certain level are indistinguishable from black, which, in my experience, was roughly equivalent to a 60% black in print. Various "green" colors may project as indistinguishable from yellow colors with any amount of red in the RGB mix tend to project much darker than they appear on the computer screen. We usually test projectors with a test slide that contains various widths of rules and all the colors we're using in the presentation.

As a compromise between avoiding eye strain due to light glare caused by pure white on one hand and, on the other hand, the need for showing data plots and to make slide printouts (both of which look terrible on dark background), I second Tufte's use of an ivory background or also Michael's use of gray shades, with a little twist: try different shades of white, e.g., Cosmic latte, Cream, Ivory, Magnolia, Old lace, Seashell, Beige, Lemon Chiffon (see Wikipedia). Make sure you test these with a projector, not just your computer screen!

An interesting discussion!

I'd like to introduce another parameter: the light output of the image source. We have a facility that is in effect a very large, very bright rear-projection system with a really well-anchored black field in its dark state. The brightness of the system was set assuming that the ambient light in the room would be on, allowing the speaker to be clearly seen (based on the bias that the presenter should be the main focus of a presentation, generally) and allowing the other participants to see their notes, other participants, etc. Might the custom of turning off lights for projection be an accommodation for older generation projectors, from magic lanterns to Ektagraphic Carousels to recent small portable projectors?

Regardless of how we got here, people presenting white background slides in this facility with the lights subdued find that their audience is often vocally uncomfortable with how bright the slides were. Turning the ambient lights back on relieves this discomfort. Dark backgrounds with contrasting bright text are easier to look at as well.

What effect does the emergence of large, bright, self-lit displays (such as large flat-screen) have on the answer to the question posed?


What is the most readable screen font? - Psychology

A document or application is considered accessible if meets certain technical criteria and can be used by people with disabilities. This includes access by people who are mobility impaired, blind, low vision, deaf, hard of hearing, or who have cognitive impairments. Accessibility features in Adobe Acrobat, Adobe Reader and in the Portable Document Format (PDF) make it easier for people with disabilities to use PDF documents and forms, with and without the aid of assistive technology software and devices such as screen readers, screen magnifiers, text-to-speech software, speech recognition software, alternative input devices, Braille embossers, and refreshable Braille displays.

The Web Content Accessibility Guidelines (WCAG) 2.0 (ISO/IEC 40500:2012) and the PDF/UA (ISO 14289-1) standard cover a wide range of recommendations for making content more accessible to people with disabilities. One benefit of following these guidelines is that content becomes more usable for all users. For example, the underlying document structure that makes it possible for a screen reader to properly read a PDF out loud also makes it possible for a mobile device to correctly reflow and display the document on a small screen. Similarly, the preset tab order of an accessible PDF form helps all users—not just users who rely on the keyboard—complete the form more easily.

Overview of Portable Document Format (PDF)

The PDF format is the native file format of the Adobe Acrobat family of products. The goal of this format and these products is to enable users to exchange and view electronic documents easily and reliably, independently of the environment in which they were created. PDF relies on the same imaging model as the PostScript® page description language to describe text and graphics in a device-independent and resolution-independent manner. To improve performance for interactive viewing, PDF defines a more structured format than that used by most PostScript language programs. PDF also includes objects, such as annotations and hypertext links, that are not part of the page itself but that are useful for interactive viewing and document interchange.

A logical tagged structure tree is used within each document to provide a meaningful reading order for content, as well as a method for defining structural elements role and relationship to page content. Within this tag structure, other properties such as alternative text and replacement text can be provided.

Determine the Accessibility Path for each PDF Document

PDF files are created in a variety of ways, from a variety of applications, and for a variety of purposes. Achieving the desired accessibility goals for an individual PDF file requires understanding the nature of the PDF and its intended use. Adobe Acrobat Pro DC provides several tools including the Make Accessible Menu in the Action Wizard mode and the Accessibility Checker to assist authors in evaluating and fixing issues that can impact accessibility.

The Adobe Acrobat Pro DC Accessibility Guide: PDF Accessibility Repair Workflow document provides details on how to assess existing PDF files for accessibility. By following these procedures in the recommended order, authors can efficiently proceed through the analysis of a PDF file in a systematic fashion. Systematically ruling out or confirming certain characteristics found in a PDF file will guide the author to the most appropriate path for making an individual PDF document accessible.

Note: These Best Practices techniques require access to Adobe Acrobat Pro DC. Adobe Acrobat Reader DC and Adobe Acrobat Standard DC do not have the complete set of tools needed to create and validate PDF documents for accessibility.

Start with an Accessible Document

The PDF format is a destination file format. PDF files are typically created in some other application. Optimally document accessibility should begin in the native document format. For example, many documents are created in a word processing or desktop publishing application, and then exported as PDF documents. There many things that can be done in native document applications to support accessibility, such as adding alternative text for images defining structural headings, lists, and data tables providing document language and setting document properties such as titles. Adobe desktop publishing applications such as Adobe InDesign and Framemaker support these features, as well as other word processing applications such as Microsoft Word. For information on building accessibility into documents created with Adobe products visit the Adobe Accessibility website. To gain assistance on adding accessibility into Microsoft Word documents prior to conversion to PDF format please visit the Microsoft Enable website. Making the native document accessible allows for less work when changes are made to the native document and the PDF document is regenerated.

If the native document is not available, in most cases, the document can still be made fully accessible. Without accessibility in the native format there will likely be more manual work required in the PDF to properly tag the document. There are some items such as choosing sufficient contrast between foreground and background colors that must be implemented in the native document.

Characteristics of Accessible PDF files

Accessible PDFs include but are not limited to the following characteristics:

A document that consists of scanned images of text is inherently inaccessible because the content of the document is a graphic representing the letters on the page, not searchable text. Assistive technology software cannot read or extract the words in a graphical representation. Furthermore, users cannot select or edit the text or manipulate the PDF for accessibility. Scanned images of text must be converted into to searchable text using optical character recognition (OCR) before addressing accessibility in the document.

Fonts that allow Characters to be Extracted to Text

The fonts in an accessible PDF must contain enough information for Acrobat to correctly extract all of the characters to text for purposes other than displaying text on the screen. Acrobat extracts characters to Unicode text when you read a PDF with a screen reader or the Read Out Loud tool, or when you save as text for a Braille embosser. This extraction fails if Acrobat cannot determine how to map the font to Unicode characters.

Interactive Labeled Form Fields with Accessible Error Messages and No Timing

Some PDFs contain interactive forms that people fill out using a computer. To be accessible, form fields must be interactive that is, a user must be able to enter values into the form fields. Interactive PDF forms also have a defined tab order which allows users of assistive technology to use the Tab key in order to progress from one form field or interactive control to the next in a logical manner. Refer to the document Adobe® Acrobat® Pro DC Accessibility Guide: Creating Accessible Forms for complete details. Forms must provide identification, give tips on proper completion, and prevent errors. Form entry should not be timed unless the user can request more time.

Other Interactive Features: Hyperlinks and Navigational Aids

Navigational aids in a PDF — such as links, bookmarks, headings, a table of contents, and a preset tab order for form fields — assist all users in using the document without having to read through the entire document, word by word. Bookmarks are especially useful and can be created from document headings. These features can be accessed using the keyboard without relying on the mouse, and allow for multiple way for users to navigation content.

Document Language and Title Indication

Specifying the document language in a PDF enables some screen readers to switch the current speech synthesizer to the appropriate language, allowing correct pronunciation of content in different languages. Providing a document title allows the user to locate and identify the document.

Security that will not Interfere with Assistive Technology

Some authors of PDFs restrict users from printing, copying, extracting, editing or adding comments to text. The text of an accessible PDF must be available to a screen reader. Acrobat’s security settings can be set to protect document content while not interfering with a screen reader’s ability to convert the on-screen text to speech or Braille.

Document Structure Tags and Proper Reading Order

To read a document’s text and present it in a way that makes sense to the user, a screen reader or other text-to-speech tool requires that the document be structured. Document structure tags in a PDF define the reading order and identify headings, paragraphs, sections, tables and other page elements. The tags structure also allows for documents to be resized and reflowed for viewing at larger sizes and on mobile devices.

Alternative Text Descriptions for Non-Text Elements

Document features such as images and interactive form fields cannot be understood by the user of a screen reader unless they have associated alternative text. Though link text is available to screen reader users, it is possible to provide more meaningful descriptions via replacement (actual) text. Alternative text for images and tooltips can aid many users, including those with learning disabilities. Equivalents for multimedia, including any audio and video elements, must also be present.

Other Accessible Document Characteristics

There are additional characteristics of accessible documents including:

  • No reliance on color or sensory characteristics alone to convey meaning
  • Use of color combinations that provides a sufficient degree of contrast
  • Controls for audio
  • Use of text instead of images of text
  • No use of flashing or blinking elements
  • No focus changes without user initiation
  • Consistent navigation and identification of elements

Adobe Acrobat and Adobe Acrobat Reader Accessibility Features

Accessibility features in Adobe Acrobat DC and Adobe Acrobat Reader DC fall into two broad categories: features that make the reading of PDF documents more accessible, and features that help create accessible PDF documents. To create accessible PDF documents, you must use Acrobat Pro.

Features to Support the Reading of PDFs by People with Disabilities

All versions of Adobe Acrobat DC, Adobe Acrobat Reader DC, Acrobat Standard DC and Acrobat Pro DC provide support for the accessible reading of PDF files by persons with disabilities:

  • Preferences and commands to optimize output for assistive technology software and devices, such as saving as accessible text for a Braille printer
  • Preferences and commands to make navigation of PDFs more accessible, such as automatic scrolling and opening PDFs to the last page read
  • An Accessibility Setup Assistant Wizard for easy setting of most preferences related to accessibility
  • Keyboard alternatives to mouse actions
  • Reflow capability to temporarily present the text of a PDF in a single, easy-to-read column
  • Read Out Loud text-to-speech conversion
  • Support for screen readers and screen magnifiers
  • Support for high contrast and alternative foreground and background colors

Features to Support the Creation of Accessible PDFs

  • Creation of tagged PDFs from authoring applications
  • Conversion of untagged PDFs to tagged PDFs from within Acrobat
  • Security settings that allow screen readers to access text while preventing users from copying, printing, editing and extracting text
  • Ability to add text to scanned pages to improve accessibility
  • Tools for editing reading order and document structure
  • Tools for creating accessible PDF forms
  • Ability to set document properties including title and expose them through the title bar of the application

Though Acrobat Standard provides some functionality for making existing PDFs accessible, Acrobat Pro must be used to perform most tasks — such as editing reading order or editing document structure tags — that are necessary to make PDF documents and forms accessible (For more information see Comparison of Accessibility Features in Adobe Acrobat DC Plans).

The Acrobat Pro DC Accessibility Guide Series

Adobe has created a series of accessibility guides for Adobe Acrobat Pro DC to assist content authors in creating accessible PDF documents. There are four guides in this series:

PDF Accessibility Overview (this document)

The Adobe Acrobat Pro DC Accessibility Guide: PDF Accessibility Overview details what is meant by accessibility in the PDF file format. It distinguishes between the accessibility features of the file format, of Adobe Acrobat DC and of the Adobe Acrobat Reader application, and how the features of the software and the file format interact to achieve accessibility for people with disabilities.

Acrobat Pro DC PDF Accessibility Repair Workflow

The Adobe Acrobat Pro DC Accessibility Guide: PDF Accessibility Repair Workflow provides a step-by-step method for analyzing existing PDF files and making them accessible based upon that analysis. This workflow coincides with the workflow provided in the Make Accessible Action wizard and potential issues tested for in the Accessibility Checker tool.

Using the Accessibility Checker in Acrobat Pro DC

The Adobe Acrobat Pro DC Accessibility Guide: Using the Accessibility Checker describes the PDF accessibility checkers that are included in Adobe Acrobat Pro DC. Even if you generate an accessible PDF file from an authoring application such a word processor or desktop publishing program, you should then follow the steps in this guide in order to identify any items that may have been missed in the initial conversion, or to add PDF accessibility features that were not provided by the authoring tool.

Creating Accessible PDF Forms with Acrobat Pro DC

The guide entitled Adobe Acrobat Pro DC Accessibility Guide: Creating Accessible Forms describes how to use the forms tools within Adobe Acrobat Pro DC to add descriptions to form fields, tag untagged forms, set the tab order, manipulate tags and perform other PDF accessibility tasks. These techniques do not apply to PDF forms from Adobe LiveCycle Designer, as a separate process is provided for making LiveCycle forms accessible.


White Text on Pure Black Backgrounds

There’s also reasons why you shouldn’t use a pure black background with white text. A pure black background kills all light emitting from the screen. This makes eyes work harder and open wider since it needs to absorb more light. When this occurs, the white letters can bleed into the black background and cause the text to blur. This effect is known as “halation” and it affects users with astigmatism, which people of all ages could have.

Instead of a black background, use a dark gray background so that more light emits from it and the text doesn’t bleed. Doing this decreases eye strain and strengthens reading stamina.


14 Answers 14

It really depends on a lot of factors such as what is the frequency of certain characters that you expect and what fonts are available to you.

I did a rudimentary by creating a program that iterated through all of the available fonts I had installed on my Windows box at the time and printed a line containing each printable ascii character on to the screen in each of these font's. I repeated the test as well with different font sizes.

The results as I recall them were that Segoe UI and Tahoma were the best with respect to space utilization and readability for UI purposes at 10pt and 9pt sizes. In the short term we settled on Tahoma since Segoe UI isn't freely available for operating systems below Windows Vista. If you don't need to support Windows XP or older an Windows OS or other a non Windows OS then I would definitely go with Segoe UI otherwise I would go with Tahoma if it's available and if all else fails try Verdana. See this list for a lineup of available Windows fonts as well as information about the best of use of each.

Keep in mind as well that starting with Windows Vista I believe, Microsoft now recommends using a 9pt font instead of a 10pt font for UI elements since the Sego UI font displays much clearer than other fonts at low resolutions especially on flat panel displays.

Depending on what platform you are developing for, you may also want to look at modifying font metrics if possible. In .NET with WPF I recall there being quite a bit of ways to modify how the text is rendered to allow for condensing the space between characters and to make the individual characters more narrow. Using this type of technique you can stick with whatever font you like and just tweak it's rendering to get the results you need.

With regard to your specific example graph that you provided: for this particular graph I would recommend pivoting it so the text most likely to be read is horizontal for more natural reading. I would also place the number so that it is inside the each bar of the bar graph when it will fit with a color that stands out against whatever background color is there thus increasing the space for other things such as the labels. Laying out the bar graph as rows would make it easier to read and also to print on multiple pages if necessary. If a row layout is not possible then creating a separate key for each item in the graph would probably be reasonable and that way each bar could be place closer together as well to save space. The key would allow each bar to be labeled such as A, B, C. or 01, 02, 03. for example and the key (layed out in rows somewhere else) would give more detailed information about each.

Remember, a chart or diagram is mainly useful for getting quick visual information. If it becomes too much of a burden to the user/reader your probably best off simplifying it, consolidating some of the details of the chart, or just provide more raw data in a more tabular form.

Here is a simple listing showing Arial, Segoe UI, and Tahoma fonts at various sizes. Notice that the relative space taken up by each font is different at different point sizes.

Update: I've added another comparison below which shows a more complete listing of common characters including capital and lower case letters in each of the previously mentioned fonts with the addition of Verdana and MS Sans Serif (default UI font in Windows prior to Windows 2000). Unfortunately and in response to bobsoap's recommendation for using Verdana, it is pretty clear that Verdana is about the worst compared to the other fonts at 9pt although keep in mind that this may not hold true for other point sizes. Also size isn't necessarily always the most important detail, sometimes it's more important that a font is readable at small sizes than whether it is more compact relative to another font.


  1. Well hinted font,
  2. Viewer that correctly interprets hinting,
  3. The font has good math typography,
  4. Sans Serif is usable only for presentations.

That's what Font hinting is. And here is a good example found in Google:

And here is a comparison between Adobe Reader (left) and Sumatra PDF (right):

Adobe Reader renders better, even if the font used (CM-Super) doesn't have the best hinting possible.

And here is what good math typography means. Hidden defects in mathdesign Blackboard Bold:

And yes, thats not a defect in the viewer, they print as seen from any reader. That means, it's good to use fonts with proven quality. Not to use something that in the last minute shows its hidden defects.

And finally the Sans Serif math. Can you easily read that? I can't.

If the font is large enough, serif fonts are not an issue even on screen.

The predominant problem of serif fonts on screen is the rendering accurate of the tiny serifs without creating visual clutter. But with modern displays, modern font rendering techniques (ClearType anti-aliasing and proper hinting) and large fonts, this is not an issue any more.

The advice of using sans-serif fonts in favour of serif fonts is therefore outdated, and using serif fonts on screen has the same advantage that it has in print namely,

[…] that serifs help guide the eye along the lines in large blocks of text. [Source]

The only potential problem is that not all fonts were designed with screens in mind, and are therefore poorly adapted to ClearType rendering. A properly hinted font mitigates this.

Next-generation displays (Apple’s Retina Display) promise to make even that obsolete: their resolution is so high that the naked eye cannot distinguish individual pixels, and text looks as smooth as in high-quality print 1 .

For now, though, most displays in use still have comparably low resolutions and require properly hinted fonts for best rendering. So, in summary (for now): Use a large font that was designed for on-screen usage. Serif or sans serif is irrelvant.

For inspiration, look at the free fonts listed at the Google Web Fonts directory, especially Vollkorn or the Droid Serif font which was particularly developed with small font size in mind.

1 Ironically, the article does pretty much the opposite: it uses a small font which, though developed for on-screen usage, contains hinting errors and looks smudged:


Typeface Readability

When reading text, most people do not read or parse individual characters or even words. Instead, the eye quickly scans through text and parses patterns and groups of characters (typically 6-9 characters at a time) which are nearly instantaneously converted into meaning by the human brain. This subconscious process allows us to read and understand text content very quickly with high degrees of understanding, even though we aren't even seeing or thinking of characters and words.

It is only when characters or words are unfamiliar or introduce a barrier to that direct pattern-to-meaning process that we must pause to more closely examine or process characters or words. For optimal readability and understandability, the key is to avoid those interruptions.

Some principles to consider:

  1. Use simple, familiar, and easily-parsed fonts.
  2. Avoid character complexity
  3. Avoid character ambiguity
  4. Use a limited number of typefaces, fonts, and font variations.
  5. Consider spacing and weight.
  6. Ensure sufficient, but not too much, contrast between the text and the background.
  7. Avoid small font sizes and other anti-patterns.

Use simple, familiar, and easily-parsed fonts

Simple, familiar typefaces are easiest to parse and read because the mind already has or can quickly generate a model for the shapes and patterns of text. Unfamiliar or complex typefaces require additional time and orientation, resulting in character or word parsing (which is slow and cognitively intense) rather than pattern/block parsing (which is fast and less burdensome).

There is not a best typeface or font. Experts disagree on which typefaces provide the best readability. Some long-held beliefs, such as the idea that sans-serif fonts are better for viewing on a screen and serif fonts are better for print are outdated due to the prevalence of high resolution displays. Regardless, simplicity in typefaces is critical. The typeface should be familiar or easily-parsed so that it quickly becomes familiar. Many common and standard fonts available in modern operating systems meet these requirements.

Similarly, there is not one typeface that will be optimal for all users with dyslexia.

Typefaces should be chosen to align with the tone, messaging, and brand of the content. A cartoon font used on a bank web site, for example, would likely undermine the sense of trust and professionalism the user expects. Consider the differences between these two logos with the same text, but different typefaces.

Which of these banks would you trust more with your money?

Avoid character complexity

Simpler shapes and patterns of typographical text are more quickly and accurately analyzed by the human mind. Be careful with complex fonts, especially for long sections of text.

Avoid character ambiguity

When glyphs or characters within a typeface appear similar to another, this can introduce ambiguity which must be processed by the brain, thus impacting reading speed and understanding.

The texts above illustrate common ambiguities. The capital letters "C" and "O" and lowercase letters "e" and "o" in the Arial typeface look very similar due to the very narrow opening in the letters. This is contrasted with the wider opening and more distinct differences between "C" and "O" and "e" and "o" in the Open Sans typeface.

Similarly, capital "I", lowercase "l", and numeral "1" appear almost identical in Gill Sans, but are much more easily distinguished from each other in Verdana. Even though Verdana is a bit more complex, this minor complexity helps with disambiguation of characters.

Use a limited number of typefaces, fonts, and font variations

Each time you encounter a new typeface, font, or font variation, your mind must build a map or model of the characters and patterns to then more quickly parse words and process meaning. This requires cognitive effort and time. If the typeface is already familiar, this overhead is reduced.

Be cautious when using multiple typefaces in the same document or web page. Ensure that typefaces/fonts align with types of content, such as one typeface or font for headings and another for body text.

Consider spacing and weight

Adequate letter and word spacing can improve readability by providing greater separation and clarity between adjacent characters and words. When letters or words appear very close to each other, confusion can be introduced.

Additionally, the weight (meaning the thickness of the glyphs) can also impact perceivability and readability.

WCAG requires that no loss of content or functionality occurs when the end user overrides page styles for paragraph spacing to 200% of the font size, text line height/spacing to 150% of the font size, word spacing to 16% of the font size, and letter spacing to 12% of the font size. Ensure that your page text can be modified without it disappearing or overlapping other page content.

Ensure sufficient, but not too much, contrast between the text and the background

Text is much easier to read when there is a sufficient contrast or brightness difference between the text and the background. The Web Content Accessibility Guidelines define measures for sufficient text contrast. Tools such as WebAIM's Color Contrast Checker make it easy to check contrast and determine WCAG compliance.

Black text on a white background is the default for web content, but this combination can feel stark and fatiguing, especially for long sections of text. Too much contrast may introduce halos or echos of text characters which can impact readability, especially for some with dyslexia. While WCAG does not have a maximum contrast threshold, you may want to style text with slightly lower contrast. This page, for example, uses a very dark grey body text color on white for slightly reduced contrast.

Avoid small font sizes and other anti-patterns.

In addition to text spacing, weight, and contrast, the size of text has a significant impact on readability. Although WCAG has no minimum font size requirement, it is still a valid usability consideration.

Relative font sizes (such as percents or ems) provide more flexibility in modifying the visual presentation compared to absolute units (such as pixels or points).

The font size chosen also impacts line length&mdashthe number of characters that appear per line. Line length and other text layout considerations are covered in WebAIM's Text/Typographical Layout article.

Be careful with longer sections of text that are entirely bold, italicized, capitalized, or styled in atypical ways. These font variations can make text more difficult to read&mdashand each new variation requires some orientation by the user.


A Guide to the Best Fonts for Legal Documents

Why do legal fonts matter? After all, you’ve worked hard to become a lawyer—not a designer. But did you know that the best legal fonts can better engage your audience, communicate more effectively, and impact how others perceive your law firm’s brand ? Also, some courts have outlined the fonts that they accept, which lawyers need to follow. Lawyers spend a vast amount of time drafting legal briefs, memos, court documents, and more every day. Paying attention to how the words look will help your legal writing stand out and persuade your reader better.

In this blog post, we’ll discuss why legal fonts matter in legal documents, and the best fonts and font sizes to use in legal documents and your law firm’s website. We’ll also include some tidbits on how understanding the difference between serif and sans serif fonts can help you select the right font.