DEVELOPING THE NEGATIVE FILM.
Faller a long dish may be used, as illus trated by Fig. 199 (p. 123), or the film may be wound, gelatine side outward, round a wooden frame, as shown on page 121, and immersed in • a suitably large tank holding the developer. Each end of the film is fastened by a clip or by drawing pins. Another method is to wind the film spirally round a large drum, similar to that shown by Fig. 443 (p. 314), the developer being contained in a dish or tank underneath. Practically any developer may be used, but one which will give a bright clear image, full of detail and free from stain, is to be preferred. Amidol is very suitable for the purpose. Development is best done by the factorial system, since it will be very awkward to examine progress in the ordinary manner. This difficulty may, however, be overcome by winding the film on a glass drum having a ruby electric lamp inside it. Hardness or chalkiness must be carefully avoided, as this will appear very objectionable in the final result. Special attention should also be given
to the prevention of stains, scratches and pin- ' holes. When developed, empty off the solution • and pour in clean water, in which the film may be allowed to remain for about a minute ; or a separate tank may be kept for this purpose, if preferred. Then immerse the film in a fix ing bath composed of hypo., 2 lbs. ; sodium bisulphite (crystallised), .1 lb. ; water, 5 quarts. Leave the film in this until perfectly clear, then wash in running water for about an hour, finally treating it in a glycerine bath for five minutes, and hanging up to dry on the frame. The glycerine bath is compos d of water, 1 gallon : alcohol, 1 pint ; glycerine, 5 ozs. When perfectly dry, the film. may be rolled up, care fully wiping of any dirt or water marks on the celluloid side.