Optimization of operating parameters of video display units in text reading task: Luminance contrast, viewing distance, and character size

The purpose of this study is to determine the reading performance of operators on a desktop computer. The effects of luminance contrast, viewing distance, and character size on the speed of reading were investigated. The luminance contrast between the background and character was varied while color contrast was held near-constant. Stimuli with different levels of character size, viewing distance, and luminance contrast were considered while assessing the readability performance. The luminance contrast between the background and character (0.01, 0.15, and 1.00), character sizes (0.2, 1.5, and 4 degrees), and viewing distance (40, 50, and 60 cm) were used, and the performance of the operators were recorded in terms of words per minutes (WPM). Standard workplace design recommendations to position the center of the visual display terminal (VDT) 15 degrees and 40 degrees below horizontal eye level were used for the visually intensive readability task. An orthogonal array, the signal-to-noise (S/N) ratio, and the analysis of variance (ANOVA) were employed to investigate the above-mentioned operating parameters to determine the optimum readability performance. The results indicated that performance was better at a 15 degrees viewing angle as compared to a 40 degrees viewing angle.