Abstract— The purpose of this investigation was to determine if color differences can improve legibility and compensate for insufficient luminance contrast. Several authors previously have answered this question positively on the basis of performance experiments. We argue that a valid answer cannot be given unless subjective data are used. In four experiments, subjective ratings were collected pertaining to multicolor CRT text displays. The displays were systematically varied with respect to both luminance contrast and chromaticity contrast. The results indicate that chromaticity contrast and luminance contrast are additive only under specific conditions. Chromaticity contrast cannot improve legibility if an acceptable level of luminance contrast is present. Generally, chromaticity contrast cannot be substituted for luminance contrast.

No abstract

Video display units have penetrated into modern control rooms, replacing conventional instrumentation as a means of information presentation to the operators. In four experiments simulating a small chemical plant process, several process variable and presentation characteristics were investigated. The experiments focused on the early detection of 'oncoming off-normals' (ocons)-deviations in the process that have just begun to appear. The results show that the way information is presented and some characteristics of the signals presented affect detection performance. It is also suggested that the presence of historical information, in the form of trends, seriously hampers the early detection of oncoming off-normals.

No abstract

No abstract