Monday, July 23, 2007

Chromatic discomfort

Some interesting new research at the University of Essex in Colchester shows how narrow stripes of complementary colors can induce discomfort.

Several times I wrote about the readability of colored text, and in unrelated posts on how for example a flickering display in the periphery of the visual field can cause discomfort. Prof. Arnold Wilkins in the psychology department at the University of Essex in Colchester has researched this class of problems for decades.

For example, regarding readability he has studied how colored overlays can reduce visual stress and increase reading fluency. He has a Web page devoted to this topic.

Last year, Arnold Wilkins completed a joint project with artist and migraine sufferer Debbie Ayles on the discomfort induced by complex color images. The scientific results are presented in a poster. In summary,

  • uncomfortable images have an 'un-natural' curved power spectrum
  • they tend to have greater power at about 3 cycles/degree
  • urban images have slightly more power at about 3 cycles/degrees

Colored stripes with such spatial frequencies

  • are uncomfortable to view
  • give perceptual distortions
  • can provoke eye strain, nausea, headaches, even seizures