One of the sleeper features in Photoshop CS4 is new support for simulating color
blindness.  My fellow PM Bryan O’Neil Hughes managed the development of the feature, so I invited him to share more info in a guest blog post. Read on for details.  –J.

I’m going to let you all in on a little secret: I’m color deficient, specifically in perceiving the narrow spectrum of colors between some shades of blue and green. I’m not alone. The vision of 7-10% of males in the US are similarly deficient (as are nearly half of the male portion of DI Pro Product Management! I’m not naming names).  ["Not it."  –J.]  It hasn’t held me back; in fact, I used to print for a custom lab and I’ve been involved in professional imaging in one capacity or another for the last fourteen years. Like a lot of handicaps, you learn to work around it (and ask your wife’s advice before getting dressed ;-)).

1-3% of the world’s population (again, mostly male and varying in frequency by geography) is truly color blind. These folks are missing entire portions of the color spectrum…and often have no notion of red, green, purple, etc. For these individuals, the handicap is more than an inconvenience–it can be frustrating and dangerous.

Adobe has collaborated with the University of Tokyo and the Industrial Research Institute of Ishikawa to employ proofing abilities into Photoshop CS4 (and Illustrator CS4) that leverage CUDO (Color Universal Design Organization) technology for simulation of constrained color gamuts. These powers are baked into the profiles used by the Adobe Color Engine.  In order to see colors as a protanopia (absence of red photoreceptors) or deuteranopia (absence of green photoreceptors) user would, simply select View/Proof Setup and the type of color blindness. We support the two most common forms of severe dichromacy, these two account for the large majority of such cases.

To try the feature yourself, choose a rainbow image from the web and change proof setup. Here’s a sample image, displayed three times Photoshop–once with a regular color profile, and once each with protanopia and deuteranopia profiles applied.

Considering just how many people are affected worldwide and that this technology was both expensive and not deeply integrated prior, this is an important step forward for accessibility in Adobe applications. While seeing photos and web sites as ALL users do is very important, imagine what this means to things like maps, GPS devices, ATMs, forms, medical materials, etc.

For more information:

• David Sommers writes about Designing for the Colorblind and provides numerous examples.
• Wikipedia offers more background on the subject.