Abstract
IT is claimed in the G.E.C. Journalof February that during last year very satisfactory progress was made in developing various types of technique for improving electric discharge lamps. Unsolved problems in heterochromatic photometry and colorimetry previously stood in the way. The problem was complicated by the practical application of fluorescent discharge lamps to domestic and other forms of interior lighting. This made it necessary to measure the colour-rendering properties of the light sources in a way distinct from their colour. Although non-selectively reflecting surfaces or fabrics, such as ‘whites' or ‘greys', will have the same coloured appearances when illuminated by light from such sources, since reflection by these surfaces produces no change in the spectral energy distribution of the light, the coloured appearance of selectively reflecting surfaces, such as dyed fabrics, may be quite different. Therefore, although the colour of these two light sources is the same, their colour-rendering properties are different, and it is this latter property which it is desired to measure.
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Colorimetry of Electric Discharge Lamps. Nature 145, 547 (1940). https://doi.org/10.1038/145547b0
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DOI: https://doi.org/10.1038/145547b0