Good morning blog folks! I greet you this morning with a familiar topic from the early part of this usability series: Colors! (or "Colours!" for those of our readers who favour the use of "u" in said words).
This time around, we want to look at colors not as a product identifier like our DayQuil-NyQuil post, but as harmonized labeling. This type of "labeling" is commonly seen in medical-grade gasses.
The image you see above is a collection of oxygen cylinders whose only identification (other than the picture title that appears if you leave your mouse hover over the picture too long) is its color. Oxygen cylinders are colored specifically to allow for easy association with its contents. The learning curve for color association is mild. In addition, the mind associates colors very quickly, likely one of the reasons that stoplights are colored. In a medical setting, there is often little time to make critical decisions and colors help the human/device system operate more efficiently. Even the standard EN 1041, which outlines information to be provided by manufacturers of medical devices, considers colors in the same line as symbols. It requires that if colors are used, they should either be harmonized to a standard or defined in the instructions for use - exactly the same requirement symbols.
One of the major issues that arises with color is that not everyone can see color. It is very easy to assume that everyone can see and hear as the mean population can; however, there are a good many people that are color blind. Back to the traffic lights again!
It is said that the colors in the traffic lights are specified such that color-blind people can still differentiate between the three colors by adding tints of other colors. The challenge is that there exists a wide variance in the types of color-blindedness, and, since even studies of the user population cannot perfectly account for it, color-based design or labeling can only go so far. It is a wonderful tool, but it should also be used carefully or be a complimentary control working with several other types of risk controls, especially for catastrophic hazards.
-RTK
Image Credit: Morberg on Fotopedia