Gray-scale perceptions calculated: optimum display background luminance.
The following questions motivated this study, which summarizes and illustrates the answers. How can the number of gray levels visible on a display be maximized? How can a designer maximize the discriminability of a set of gray symbols that use only a part of the luminance range available from the display technology? Can we calculate whether particular shades of gray will be discriminable from each other? How big should successive gray-scale steps be (in luminance, reflectance, or optical density) to make them appear equal? How many discriminable shades of gray can be seen with a particular display technology in a particular light environment? What is the probability that two specified shades of gray will be mistaken for each other at a glance? How does the luminance of the screen background affect the visibility of gray symbols? Is there a single principle that describes the appearances of areas more luminous than the background (positive contrasts) and less luminous areas (negative contrasts)? Limitations on the answers are discussed, issues for further research are suggested, and applications are described.
Carter
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