Thursday, April 24th, 2008
The picture above is showing you how someone with the color blindness trait Tritanopia would see the image. Michael Deal first created the Color Matrix Library, which supports a large portion of the most common color functions available, including:
Hue, Saturation, Brightness, Contrast, Exposure, Temperature, Tint, Channels, Blindness, Colorize, Threshold, and Invert
Michael then created a canvas library that uses the Color Matrix to help us visualize what our content may look like to people who have various color blind issues. Here is what he did:
The most obvious way would be to do the calculations in CIE XYZ using confusion lines, however, <canvas> uses RGB. So youâ€™d have to convert from XYZ to RGB, run the confusion lines, then convert back to RGB. Hereâ€™s an example of what that looks like: Color Blindness Library â€” Itâ€™s great for running on a few colors, but too slow for larger images.
Matrixâ€™s are generally about as quick as youâ€™re going to get for generic color filters, so thatâ€™s what Iâ€™ve converted the formulas into â€“ compliant with Actionscriptâ€™s ColorMatrix, and other programming languages that use standard RGBA matrixâ€™s. Also, Iâ€™ve converted them into color transformâ€™s which are useful in Actionscript (ColorTransform), Pixelmator (Image… Channel Mixer), and Photoshop (Image… Adjustments… Channel Mixer).
I used data generated by Matthew Wicklineâ€™s formulas to base my blindness library. My script triangulates the hue by comparing the un-filtered, completely saturated, RGB values with the same value after theyâ€™d been run through Wicklineâ€™s formula.
Posted by Dion Almaer at 1:35 pm