Text quality metrics for visual display units:: I. Methodological aspects
A comparison of four experimental variables to measure the visual quality of text on visual display units (VDUs) is discussed. Scaled visual comfort is considered to be the most relevant psychological attribute. Visual performance, saccade length and fixation pauses during a search task approximating closely to reading are under the present conditions highly correlated with visual comfort if luminance contrast is the independent variable. All four variables are found to be satisfactory with respect to sensitivity, but it is argued that comfort scaling and the measurement of visual performance will probably suffice. Only small differences between subjects are found, suggesting that in the future a standard observer is feasible. The advantage of a print reference is argued.
vdu scaling visual comfort visual performance luminance contrast eye movements