Color contrast analyzer is one of the must-have tools for Web Accessibility. It is primarily a tool for checking foreground & background colour combinations to determine if they provide good colour visibility. It also contains functionality to create simulations of certain visual conditions such as colour blindness. The software is very simple and by choosing a combination of foreground & background colours you may see the contrast ratio using the Colour Brightness Formula and Colour Difference Formula.

For example I tryed the main text color of PHPMagazine.net websites : Foreground:#444444 Background:#FFFFFF. The result is quite intersting, since it Passed at level3 (The contrast ratio is: 10.04). The software provide also some recommandation such : Text or diagrams and their background must have a luminosity contrast ratio of at least 5:1 for level 2 conformance to guideline 1.4,and text or diagrams and their background must have a luminosity contrast ratio of at least 10:1 for level 3 conformance to guideline 1.4. Color Contrast Analyzer is a Freeware licensed under a Creative Commons License.