This tool uses W3C formulas for detecting sufficient contrast between a foreground and background color. This tool is loosely based on the Colour Contrast Check tool, but the main difference is it will provide some suggestions to use by darkening the foreground color or lightening the background color. The suggestions are based by adjusting the brightness of each color by +/-1 percent and they suggest the first color that matches passes the various formula tests. This test is not the end all, be all but it can be a useful tool when you need to bumb up the contrast between two colors.