Abstract
The whole subject of quality in lighting is recognised as a complex of inter-related elements. The limited purpose of the paper is to take up a few loose ends in a tangled skein, to attempt some tentative methods of study, and to make suggestions for further work.
There is little difficulty in identifying those qualitative elements in the lighted interior which contribute to the total visual experience. The paper attempts to show the relative influence of those elements, and to investigate two of them in some detail. The paper also reports on a programme of comprehensive appraisals of lighted interiors, and discusses the difficulties inherent in the organisation of subjective assessments, the choice of observers, and the interpretation of the results.
The two elements chosen for special study are modelling and the brightness pattern. Results are given of a subjective investigation into the acceptability of various degrees of modelling produced by different lighting arrangements and decorative schemes in a small office. Alternative methods of measuring modelling effects are discussed and attempts are made to relate these measurements to subjective judgments. A simple study of the comparative acceptability of brightness patterns has been carried out by means of an adaptable lighting system and the results of numerous subjective assessments are discussed. Much more experience of such critical studies will be required in order to guide the specification of brightness ratios. At that stage luminance design methods will be required, and the paper includes a practical example of one design method worked out in detail.
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