colorB_normal

Web safe: the name is slightly misleading. First because most modern browsers can display the millions of possible RGB colors. Second, and more important to this post, because the word safe carries a connotation that web-safe can’t quite live up to. Safe implies that everyone can equally use the colors without any adverse consequences. For the less than 1% of the population with certain types of color blindness, there are very real consequences.

Below are three images that give representations of how people with three types of color blindness might see the subtractive CMYK and additive RGB colors. (It is important to note that these images are just representations meant to illustrate a point, they are not meant to serve as a basis for planning color schemes or answer those philosophical questions about whether the red I see it the red you see.)

The most common type, called dueteranopia, means greens and reds are almost indistinguishable:

colorB_deuteranopia

The other two, which are rarer, are protanopia and tritanopia respectively:

The other two, rarer, are protanopia and tritanopia respectively:
colorB_protanopia
colorB_tritanopia
Now as technical communicators we have an obligation to provide the same information, both written and visual, to all potential users. I can think of two ways that a design could hinder someone with one of these forms of color blindness:
  1. A foreground text and a background color may not provide sufficient contrast to someone with one or more forms of color blindness. Now no amount of effort that goes toward tailoring a message to a specific audience is justifiable if the audience finds the text difficult or impossible to read. This seems to be something that is much more important in web design because color can be so much more prevalent. The best way to avoid any sort of problem is to stick with a black and white; while not necessarily the pinnacle of aesthetic web design,  no one can mistake a black letter for a white rectangle. And there is no way to increase the color contrast of a black-white combination.
  2. And this is a more difficult problem to solve. Consider a message that relies heavily on color-coding; say one sort of heading is in red text while another is in green text. Now each color carries a specific meaning and provides context to the paragraphs beneath it, but that context is lost on a very small portion of users. Because the color code is useful to the majority of users, it would be inefficient to abandon it altogether. Some sort of redundancy in the visual cues would be required. One idea that comes to mind would be texture: thin, background diagonal lines, which could be color coded themselves with no detriment to the color blind, could be used with one color and not the other.

If you can think of additional ways technical communicators should accommodate for color blindness, we would love to hear them.

One Response to “Color blindness amidst web-safe colors”

  1. Alex Grantz says:
    December 17, 2009 at 9:02 PM

    Cool stuff… I’ll definitely have to keep this in mind the next time I design a site. I tend to always use black/white for text since you can never really go wrong with it, but I’ll pay special attention to this in the future.

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