LATITUDE OF PLATES AND PAPERS In negative-making variations may be made in exposure, within moderate limits, without any loss of printing qualities. The latitude is, however, influenced considerably by the subject and the conditions. A subject with good con trast, or exposed in a clear and brilliant light, will allow more latitude than one deficient in contrast exposed in a dull light. With the latter and in copying, there is practically none at all.
It must be recognised that it is only in over exposure that latitude can really exist. Loss of quality is inseparable from under-exposure. In all subjects, however, it is possible to compen sate for errors in exposure to a moderate extent, if the error is known before commencing to develop. A modified solution may be applied that will have the property of compensating for the extra exposure given. (See also " Exposure, Incorrect.") With regard to papers, in a platinotype print there is practically no latitude ; in a cold bath the development may be shortened to save au over-exposed print, but the result is distinctly inferior. An over-exposed silver print may be
slightly reduced by a long immersion in the com bined toning and fixing bath, but the quality suffers. A carbon print has more latitude than any other photographic printing process, as errors can be compensated when the print is partially developed : that is, the stage at which the error is discovered. Within moderately wide limits, the loss of quality is inappreciable. With bromide prints a moderate latitude could be secured by modifying the developer before com mencing to develop. After development is com menced, compensation can only be made for over exposure by shortening the duration, but this produces results that are so inferior to those pro duced by correct exposure and full development, that it cannot be called true compensation.