While perusing Hacker News I ran across a single-page site called Contrast Rebellion— which I understand has created a bit of controversy.

I think the point espoused by Contrast Rebellion is both well-made and well-taken (despite the host of straw-man style arguments to the contrary); however, I feel that—in most designs—contrast arises fairly organically. If I can’t read my font, or there isn’t enough contrast in my color palate, then I know that the people from whom I solicit opinions are going to mention that before saying anything else.

If only we were all so lucky. ☺

On the topic of color contrast the W3C defines Success Criterion 1.4.3 saying:

Contrast (Minimum): The visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except for the following: (Level AA)

• Large Text: Large-scale text and images of large-scale text have a contrast ratio of at least 3:1;
• Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement.
• Logotypes: Text that is part of a logo or brand name has no minimum contrast requirement.

There is a formula for calculating the contrast of two colors available at the paciello group— they also have a Contrast Analyser that you can download for Mac and Windows.

Alternately, you could skip the download and the hand-cranking of numbers and enter your hex codes into the Luminosity Colour Contrast Ratio Analyser

edit—11/23/2012

My new favorite tool for contrast checking is Lea Verou’s constrast checker

Looking at popular websites contrast

The genesis of this exercise was to review websites I have built and to review some other popular sites so lets do that …

The contrast on this site

It’s pretty good right? The text you’re reading I mean— it’easy to read, contrast-wise anyway.

• Text color: #444444
• Background color: #f8f8f8
• Contrast-ratio: 9.17:1
• Analysis: Pretty amazing.

edit—11/23/2012

You’re looking at Text color: #8f8d80 which means that the contrast ratio here has dropped to 3.1:1—which meets the success cirterion for the current text-size of 24px! (which is, admittedly, very large, but whatever, I ain’t scared).

Apple’s nav bar

Apple’s nav bar is a gradient, so this analysis is for the color at the lightest point of the gradient versus the text

• Text color: #FFFFFF
• Background color (again, at the lightest part of the gradient): #727272
• Contrast-ratio: 4.81:1
• Analysis: Passed at Level AA for regular text, and pass at Level AAA for large text (18pt or 14pt bold)—Apple’s nav text is SVG (ostensibly for the new retina displays), but it seems to be about 13pt–14pt. A little low-contrast perhaps, but not too drastic.

Google’s account settings bar

The Google account settings bar has always seemed to be fairly low-contrast to me—let’s test a theory.

• Text color: #666666
• Background color: #F1F1F1
• Contrast-ratio: 5.08:1
• Analysis: Passed at Level AA for regular text, and pass at Level AAA for large text (18pt or 14pt bold)—better contrast than Apple; however, the text in this image above is 13px/27px Arial,sans-serif at the default font-weight which is close, but not quite ideal.

Out of curiousity I decided to see what these recommendations would look like for Google in practice—answer: more readable, arguably less aesthetically appealing (see below).