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!