FOREWORD

The two volumes of the present CIE Report No. 19/2 represent a complete replacement for CIE Report No. 19 which was presented to the CIE by the committee during the 1971 Congress in Barcelona and subsequently published by the CIE in 1972. The "unified framework of methods for evaluating visual performance aspects of lighting" described in Report No. 19 is now to be replaced by the fully quantitative "analytic model for describing the influence of lighting parameters upon visual performance" described in the two volumes of Report No. 192. The considerable expansion of coverage of visual performance aspects of lighting to be found in the present two volumes was made possible by meetings of the committee in Berne, Edinburgh, Florence, Amsterdam, London, Paris, Munich , Karlsruhe , and Paris between 1971 and 1978.

The two volumes of Report No. 19/2 contribute to the work of the CIE by providing potential bases for (a) determining selective standards of task illuminance based upon visual performance criteria for different task conditions and observer ages, (b) evaluating the extent to which actual lighting installations meet these criteria, and (c) Providing measures of overall performance of tasks with significant visual components for use in cost-benefit analyses of lighting.

It is to be emphasized that, although the analytic model described in the present two volumes of Report No. 19/2 is believed to have potential usefulness to the CIE in the areas of lighting applications listed above, the present two volumes do not describe application procedures for these purposes. It is anticipated that the development of such procedures will be undertaken in the future by appropriate agencies of the CIE and reported separately.

The present Volume I of CIE Report No. 19/2 presents a description of the technical foundations of the analytic model insofar as it describes the effects of lighting parameters upon "visual performance potential, "a measure of the maximum visual performance to be expected under various lighting situations. Volume II presents a summary description of the analytic model, tabular and graphical representations of the effects of lighting parameters upon visual performance potential, and application guidelines including mathematical methods for estimating task performance and overall performance from visual performance potential. It is suggested that the visual performance specialist with respect to application guidelines or the relationships between task performance and/or overall performance and visual performance potential. (It is suggested that the applications engineer begin with Volume II, turning to the present Volume I if additional information is desired with respect to the technical foundations of the model.)