New tool: evaluate color contrasts for WCAG 1 and 2

September 7, 2008

Topics: Accessibility.

There are, of course, a lot of color contrast evaluation tools available on the web. Roger Johansson published a list of 10 color contrast checking tools last September, and there are undoubtedly more out there yet.

In fact, for a long time, I’ve primarily used the three tools by Gez Lemon which are on that list:

I certainly have no intention to stop using the Firefox Extension, but I’ve been irritated by the other two tools for a long time for two reasons. First, the simple fact that there are two tools. Obviously, the first was written long before the second, but given that they are testing the same pieces of information, it would be nice to be able to conduct the test with a single test. The second is that the tools have rather poor usability: the original color contrast analyzer, at any rate, gives a lot of information and it can be rather difficult to pick out the key bits: the actual contrast between the items and whether or not you’ve passed or failed.

This tool I’ve just placed on the web (“released” is far too glorified for this) is purely intended to combine these two functions into one tool and to provide more readable output.

I haven’t checked the output as thoroughly as I might have; there may well be bugs. Let me know if you notice one!

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5 Comments on “New tool: evaluate color contrasts for WCAG 1 and 2”

  1. Cheers. I’ll take a look at that.

  2. I think it’s pretty acceptable. I’ve seen a number of arguments that it’s “too strict,” but given that it’s actually less strict in many ways than the color contrast tests previously used to test contrast compliance, I think it’s reasonable.

    The reasoning behind the decision can be found in Understanding WCAG (Web Content Accessibility Guidelines) 2 / Contrast (Minimum). That document includes links to the relevant specifications used for their decision making.

  3. What do you think of the current 5:1 ratio for Level-AA in WCAG (Web Content Accessibility Guidelines) 2.0?

    We find it’s a little too strict for the default version of a website. WCAG 2.0 does allow for the stronger contrast to be on an alternative stylesheet, but I prefer to have the default as accessible as possible.

    It would be nice to see the research which led them to that figure.

  4. I’ve looked at that page before, but (to be honest) I’ve never actually downloaded it. On the whole, for something as simple as a color comparison, it seems a bit much to download software — although the fact that it does simulations of visual disabilities is appealing.

    Thanks, David!

  5. Hi Joe,

    You might want to check out the latest version of the Color Contrast Analyzer. It’s something that the company I work for use a lot when we’re designing pages.

    The UI could be friendlier though, I agree.