Pacific Sciences and Engineering conducted an initial study to determine a methodology for evaluation alternate background colors. Four “displays” were created that would enable evaluation of entire problem space. Pacific Sciences chose not to conduct follow-on due to heavy workload from Navy project.
• What variables have the greatest affect in selecting the background / foreground color palette for a given ambient light source?
• What characteristics, aspects or principles of ambient lighting conditions influence the usability of sets of color on an operator display?
• What characteristics, aspects or principles of the display device (screen, monitor, LCD panel) influence the usability of sets of color on an operator display? (examples include viewing angle, contrast ratio, brightness, and treatments.)
• What set of ambient lighting conditions and color sets are well suited to popular background colors:
o Gray (227, 227, 227)
o Light blue (223, 228, 232)
o Sky Blue (183, 205, 236) and (125, 182, 223)
o And (245, 250, 255)
• How can these findings be applied to other sets of colors? For example, are there good conditions for black background or white background?
• Are there color schemes with a fixed background color that could suffice across all ambient lighting conditions?
• How can these findings provide a starting point when considering other situations like uncontrolled environments outside the central control room? Standard office, roving operator in sunlight and shadow, airport gate lounge, etc.
• How does color blindness affect the perception of the usability of sets of color on an operator display?
Gray background for control room displays has become the industry norm for several reasons. Black objects on gray background allow for fast data recognition and response time. It focuses the operator’s attention on foreground objects and color differences are accentuated on an achromatic background.
Despite the popularity and high level of adoption, there is a lack of empirical evidence which conclusively demonstrates that gray background optimally reduces eyestrain or glare, or optimally improves legibility or operator response time. It may be better than black backgrounds, but is gray really best? Research suggests that there is no general agreement on optimal background color. However, under various ambient conditions there are better background and foreground color palette combinations. For instance, eyestrain is caused by muscle fatigue. One cause of muscle fatigue is low text legibility. Low achromatic contrast decreases legibility suggesting that other combinations of background-foreground colors can significantly affect operator performance.
While gray background is the color of choice today, there are several arguments that suggest it may not be optimal. Pure colors produce an after image that causes eye fatigue, so certainly non-pure background colors are preferred. But gray is only one choice – there are others. High luminance contrasts provide high legibility suggesting that background vs. foreground color palette selection is just as important as the background color. Light background produces less screen reflection and glare so display background colors should be light with high luminance contrast foreground objects. Consequently display backgrounds should be light, but not pure white. They don’t have to be gray either. Other colors, such as light shades of blue are likely to be good background colors.
There is anecdotal evidence that suggests the high variability of monitor types and quality along with ambient lighting conditions have a significant effect on the usability of sets of colors on the operator display. These affects must carefully be studied and accounted in the research. In addition, color blindness may alter the perception and results of the usability of color sets and needs proper consideration.
Note: This project only funds Phase I. Information about Phase II deliverables can be found in the proposal from PSE which has been uploaded to this webpage
Phase I
Outbrief at May 2015 COP meeting enumerating results of literature review and analysis
on outstanding questions, and an initial experiment design for COP feedback that includes specific variables to be tested and the approach, and a plan and schedule for the Phase II study. The design will be deliberately somewhat low-fidelity so that COP feedback and specific requirements can be effectively incorporated.