FACTORIES, PHOTOGRAPHING IN Taking photographs in factories or workshops presents difficulties from several independent causes. The first is that work in progress can not always be stopped while the exposures are made, and the consequent movement cannot always be prevented. Then machinery and shafting in constant motion introduce the serious element of vibration, and, in addition, smoke and moisture are inseparable from some kinds of work, increasing the difficulties of securing good negatives. When the nature of the work will allow it, the negatives should be taken during the dinner-hour. The camera can be set, everything arranged as desired, the subject focused, and everything made ready for the exposure beforehand. Then the plate can be exposed under the best possible conditions. A stop is almost always necessary for secur ing good definition throughout.
When figures have to be included and the work shown under its normal conditions, the case is different. The exposure must necessarily be short so as to avoid movement of the principal figures. Frequently, a large aperture is neces sary in order to shorten the exposure sufficiently, and it may be quite impossible to secure the degree of sharpness in the different planes that the photographer would desire. In that case,
the principal objects must be rendered as crisp and sharp as possible, and the other parts must simply take their chance. Considerable assist ance may be given to the workmen that are included by the manner of posing. If they can be given a little support, by resting on a tool, or putting one of their hands on a machine, how ever slight the support may be, it will materially assist in avoiding movement during the exposure. A longer exposure can be given without appre ciable movement. A single machine with one or two figures should cause no difficulty. In. subjects of this kind, duplicate exposures should always be made.
Any windows that are in front of the camera. and included in the picture should be covered during nine-tenths of the exposure, and, if possible, the covering should be outside. Win dows in front of the camera, but not included in the picture, should be covered during the whole of the exposure, unless the lens can be shielded from them as described under the heading. " Interiors, Photographing."