Abstract
THE Illuminating Engineering Society has issued a list of the values of illuminations which are recommended for various purposes. It has been prepared by the Technical Committee of the Society, and copies of the full recommendations can be obtained from the Honorary Secretary, I.E.S., 32 Victoria Street, S.W.I, price Qd. Since the candle-powers of electric lamps are known and the distance of the lamps from the work bench can easily be estimated, it is not difficult to estimate the candle-power. The committee recommends that if the task requires both discrimination and response, the foot-candle value should be at least 50. For severe and visual tasks such as fine engraving, sewing of dark goods, and discrimination of fine details of low contrast, the foot-candle value should not be less than 25. For prolonged critical visual tasks such as proof-reading, type-setting, drawing, reading, fine machine-work, fine assembling and use in large stores, a foot-candle value between 15 and 25 is recommended. A foot-candle value of 8-15 would be suitable for visual tasks such as detailed office work, skilled bench work and sewing on light goods and for retail shops. For less-exacting visual tasks, such as general office, large assembly work and classrooms, 5 10 suffices. For work of a simple character not involving close attention of fine details, 3-5 foot-candles is suitable. For casual observation where no specific work is performed, 2-4 foot-candles is regarded as sufficient.
Article PDF
Rights and permissions
About this article
Cite this article
Recommended Values of Illumination. Nature 138, 238 (1936). https://doi.org/10.1038/138238b0
Issue Date:
DOI: https://doi.org/10.1038/138238b0