The Use of Colour

• Colour may be used to increase the inherent attractiveness of an activity. This is especially important with younger users.
• Children respond best to saturated primaries red, yellow, green and blue.
• Avoid saturated colours when designing for TV display. Saturated colours produce a 'bleed' effect on TV screens, as opposed to computer monitors.
• Hartley (1993), p.101, talks about the need to select colour combinations carefully and to test user colour-combination preferences. She describes "chromosteropsis", a phenomenon which results from putting "cool" and "hot" colours together, e.g. bright orange next to bright blue. Such colours come into focus for the eye at different distances and the viewer may make head movements back and forth or rapidly blink in an attempt to refocus on different screen areas. The phenomenon can cause the viewer to feel uncomfortable and experience dizziness and nausea.
• Too many colours on a screen makes reading difficult. (Hartley (1993), p.101)
• Colour may also be used for the more effective communication of screen information, --for map-based information and for route-identification and selection, -- by highlighting what is important. Hartley (1993) recommends squinting at a display from a distance of 1.5 to 2m. Colours which stand out (or have visual conspicuity) indicate dominant objects. Too many dominant objects creates confusion.
• To reduce flicker at screen edges (the eye is sensitive in this peripheral region) use muted or mid- to dark-gray colours there.
• Colour blindness results in the confusion of reddish hues with greenish hues and yellowish reds with yellowish greens. Opposing red with cyan and yellow with purple reduces misinterpretation.
• To avoid flicker, avoid bright colours at screen edges.
• If possible, check the effect of the actual ambient conditions on the screen colour appearance.
• Check the image resolution of the target display and design accordingly. 24bit images will adopt a posterized (flattened) look when shown on an 8bit or less display.

Bibliography

Hartley, R. (1993), "Guidelines for Multimedia Usage", Proceedings of the 11th Annual Conference of SIGDOC '93, pp.100,101