In this age communication through computer is growing at a very fast rate. Need of the hour is to manage the use of computer in such a way that gives fastest communication. Several factors are responsible for efficient and fast communication. Readability task is one which is widely done on computer. Out of several parameters in this paper three parameters illumination level, viewing distance and text/background color on readability task performance of computer operators is analyzed. The readability task, in the form of English text, was presented to the participating subjects and their performance, measured in terms of number of words read per minute, was recorded. Three levels of each parameter have been considered in the study. An orthogonal array, the signal-tonoise (SIN) ratio and the analysis of variance (ANOVA) were employed to investigate the operators performance efficiency. Results showed that at the illumination level of 300 lux, viewing distance of 60 cm, and for black text on white background, the subjects were quite comfortable, efficient and read maximum number of words per minute.
