100 Things You Should Know About People: #9 — Blue and Red Together is Hard On Your Eyes (Chromostereopsis)


Alternating blue and red bars
Alternating blue and red bars

Red text on a blue background
Red text on a blue background

What is it about red and blue? — When lines (or letters) of different colors are projected or printed, the depths of the lines may appear to be different; lines of one color may “jump out” while lines of another color are recessed. This effect is called Chromostereopsis. This effect is strongest with red and blue, but it can also happen with other colors (for example, red and green).

So what? — In addition to causing a depth effect, chromostereopsis can also be annoying and hard on the eyes. It is fatiguing. Although there are different theories as to why your eyes react to these color combinations in the way that they do, the important thing to remember is that they do.

What should you do about it? — If you are a visual or web designer make sure that you are not using red and blue together in this way. I still find web sites that have this color combination. Here are a few!

Example of a website with red and blue
Example of a website with red and blue
Example of a website with red and blue
Example of a website with red and blue
Example of a website with red and blue
Example of a website with red and blue

What examples have you found?

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12 Replies to “100 Things You Should Know About People: #9 — Blue and Red Together is Hard On Your Eyes (Chromostereopsis)”

  1. Thanks for making a point of how difficult red and blue is to see. I have red-green color blindness, and it seems worse for me (maybe not). I still see so much of this that I thought it just because of my color blindness.

  2. Argh, they hurt my eyes.

    Actually, a good rule of thumb is to go with heraldic rules. Under medieval heraldry there were two “metals” – white (silver) and yellow (gold) and five “colours” – green, red, blue, black and purple. The rule was that you never put a colour next to a colour, or a metal next to a metal. The principals are still largely adhered to in flag design to this day, with some exceptions.

  3. The main thing if you HAVE to use Red an Blue, is to use NEUTRAL “colors” as separators or “white space”.

    White works great, so if you have literally WHITE space, the red/blue combination won’t be so annoying as if they were placed together.

    The company I work for has red and blue as corporate colors and I hate it. But the use of lots of white helps reduce the problem.

    Personally I would not use colors so bright and vivid together.

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