Abstract
The problem is stated and is followed by a description of methods of measuring and specifying colour and colour rendering properties, with particular reference to tubular fluorescent lamps.
It has been found desirable in Great Britain to specify the colour characteristics of these light sources in terms of both their colour rendering properties expressed as percentage luminance in eight spectral bands, and their colour appearance in C.I.E. chromaticity co-ordinate limits. Typical forms of colour and spectral band specification are indicated, and a preferred form of block diagram is shown in which the percentage luminance values in the eight spectral bands are plotted on logarithmic ordinates.
New and more accurate measuring apparatus is described, to enable lumens, trichromatic co-ordinates and luminance in eight spectral bands to be measured directly on the C.I.E. system in quick succession in the one apparatus. The accuracy of such precision instruments may make it possible ultimately to specify colour rendering properties in terms of percentage luminance in spectral bands alone.
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