Ventilation and heating, lighting and seeing / issued by the Industrial Health Research Board of the Medical Research Council.

Date:
[1943]
Catalogue details

Licence: Public Domain Mark

Credit: Ventilation and heating, lighting and seeing / issued by the Industrial Health Research Board of the Medical Research Council. Source: Wellcome Collection.

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    than it really is. This is being ‘“‘penny wise and pound foolish’’, for, in the long run, bad factory lighting never pays. Many investigations have shown that it lowers output, and its less easily measured ill-effects are certainly far-reaching and wholly uneconomic. Principles of Good Factory Lighting (a) The Need for General Brightness. Light in the factory is required not only for the purpose of seeing the work easily. One of its most important functions is to brighten the whole surroundings in which work is done. Good lighting makes us feel cheerful, alert, and willing to work. Brightness and colour influence our feelings, and these feelings have much to do with whether we are energetic and efficient or apathetic and inefficient. A dim factory is usually dismal and depressing, a bright one “‘as good as a tonic”’. It is not easy to over-rate the effects of brightness in the factory on the general outlook of the workers. Good general lighting is therefore important for this reason alone. And the general appearance of brightness will be much increased if walls and ceilings, plant and machinery are painted in pale colours, such as cream, instead of in dingy greys and browns. Light colours also help to prevent glare, which is frequently due to the extreme contrast of a bright light seen against a dark background. Good general illumination in all parts of the factory also has other obvious advantages. It permits safe and rapid movement of persons and materials about the factory; it makes supervision and cleaning easier, and it is sufficient for the satisfactory performance of much of the work. (b) Lighting the Job. There are many jobs, however, for which the lighting needs special consideration. In order to avoid eyestrain, and also to get maximum efficiency, it may be necessary to provide addi- tional local lighting, or perhaps to arrange for light to fall from a particular direction. As everyone knows by experience, the finer the details to be seen, the better the light required. But it is not generally known that the amount of light needed increases much more rapidly than the “‘fine- ness” of the work. For example, if one job is twice as “‘fine” as another, much more than twice the illumination is needed to see it without undue difficulty. This is one of the “laws” of seeing disclosed by scientific investigation. Hence it may be necessary to have con- siderable differences in lighting for different jobs, in order to make it possible for each of them to be done, as far as possible, with equal efficiency and comfort. More than a hundred times as much light is needed for the “finest” as for the ‘“‘roughest”’ work in factories. Measuring Light Light can easily be measured with a light meter. This instrument can be obtained in a very small and convenient size for factory use, and it measures light in units known as foot-candles. The light meter
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