Three tools to help you make colorblind-friendly graphics by Alex Duner.
From the post:
I am one of the 8% of men of Northern European descent who suffers from red-green colorblindness. Specifically, I have a mild case of protanopia (also called protanomaly), which means that my eyes lack a sufficient number of retinal cones to accurately see red wavelengths. To me some purples appear closer to blue; some oranges and light greens appear closer to yellow; dark greens and brown are sometimes indistinguishable.
Most of the time this has little impact on my day-to-day life, but as a news consumer and designer I often find myself struggling to read certain visualizations because my eyes just can’t distinguish the color scheme. (If you’re not colorblind and are interested in experiencing it, check out Dan Kaminsky’s iPhone app DanKam which uses augmented reality to let you experience the world through different color visions.)
As information architects, data visualizers and web designers, we need to make our work accessible to as many people as possible, which includes people with colorblindness.
…
Alex is writing from a journalism perspective but accessibility is a concern for any information delivery system.
A pair of rather remarkable tools, Vischeck, simulates colorblindness on your images and Daltonize, “corrects” images for colorblind users will be useful in vetting your graphics. Both are available at: http://www.vischeck.com/. Plugins for Photoshop (Win/Mac/ImageJ).
Loren Petrich has a collection of resources, including filters for GIMP to simulate colorblindness at: Color-Blindness Simulators.