Color blindness. Part 2 of 3 http://www.colblindor.com/2007/01/23/confusion-lines-of-the-cie-1931-color-= space/ Part 1 http://www.colblindor.com/2007/01/18/cie-1931-color-space/ Part 3 http://www.colblindor.com/2007/02/02/color-blindness-test-based-on-confusio= n-lines-of-the-cie-1931-color-space/ WARNING 1 - stay away from the popups (as is often a good idea). (How many CIE 1931 ringtones does a man need?)(!) Warning 2 - James C Maxwell was here, as well. Doesn't bode well for simple understandings :-) In 1855 J. C. Maxwell said: =93Find two for a colorblind undistinguishable colors. Mark them on the CIE diagram and draw a line through them. This line will connect all colors which can=92t be told apart by the colorblind perso= n. You then can find more lines and all of those lines are either parallel or meet in a single point.=94 Russell _colourblindness -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist