Gaming is a visual medium, and it's amazing to think how much information we have to take in almost instantly to play games. Especially in action games, we need to be able to quickly take notice of subtle movements and the state of numerous dials and displays that show us how well or poorly we're doing in the game. To do that, we have to be able to absorb a large amount of color information. What does that soldier's uniform look like? Is that a red or green mark above an alien's head? Is he on my side, or is he an enemy? Now imagine that much of this crucial information was removed from a game; the challenge of dealing with situational awareness would increase very quickly.

That challenge is precisely the one faced by people who are colorblind, which is a rather common genetic problem. A reader named Tim McDaniel contacted us about this matter, and his examples were thought-provoking. "One specific gaming example that always frustrates me is Battlefield 2142. I love the game, but the flags of the two teams are not distinct enough on the HUD, at least to me. I honestly can't tell you what color they are. Red, green, yellow, brown?" he told Ars. "I usually end up trying to distinguish them by brightness because one looks slightly brighter to me, but that is so slight it's still tough."

Your eye differentiates color by using three sets of cones that register red, green, and blue. When one or multiple sets of cones become less sensitive, you begin to have problems telling certain colors apart. Some people can go through their entire life not knowing there is anything wrong with their eyes, as a specialized visual exam is needed to test for specific forms of colorblindness. Others have deficiencies so pronounced they have to rely on the position of the active light at traffic signals instead of being able to tell the difference between red and green at a glance. There are many different forms of color-blindness, but the most common involves difficulty distinguishing shades of red and green (plus related colors).



Super Puzzle Fighter II Turbo as seen by someone with normal eyes and

by someone with Deuteranopia (a red-green color deficit)

These colors often convey critical information in games. "In many first-person shooters, you'll come across closed doors with lights on the doors that indicate if they are locked or not. These are usually red or green, and I often can't tell the difference. This is a minor annoyance usually, but if it's the difference between life and death, frustrating," McDaniel told us. "Countless puzzle games that rely on matching colors are unplayable to various degrees. Even Hexic, a great game which gets it mostly right in letting you turn on shapes to augment the colors, still has the deadly 'bomb' tiles that only differ in color." He's not alone, either. While studies don't agree on specific numbers, color blindness affects somewhere between four and eight percent of the male population. Inheritance of red-green colorblindness is linked to the X-chromosome, so women are much less at risk than men.



Mario and Luigi are nearly indistinguishable to someone with Deuteranopia in New Super Mario Brothers multiplayer

What can developers do? The fixes are relatively simple to implement. Any time color-specific information is used as a game mechanic, give multiple options for those colors. A simple shift to different hues, or even a drastic increase in contrast between two colors would make these issues go away for color blind individuals. Patterns and shapes can also be used to great effect; a flag with wide stripes across it would be fix the issues people experience in games like Battlefield 2142. Even though there are simple solutions to a problem that affects a large number of gamers, it's usually not on the "short list" of concerns, as McDaniel points out. He should know, he works on video games himself.

"I work at Aspyr, and was one of the

Engineers on the Windows port of Guitar Hero III. In Guitar Hero, the notes are

colored, but I never used the colors, relying only on position, even

when first learning to play. Does anyone use the colors?" he asked, semi-rhetorically. "I wouldn't

know."