Early Work In Photography
A Text-book For Beginners

26 Early Work in Photography. necessary to exclude the blue and violet rays in order to have what is known as a “safe” light. Blue and violet light cannot pass through red glass, as such glass will only trans- mit the heat rays: red and yellow. We must bear this fact in mind while providing illumina- tion in the otherwise darkened chamber. The chemical operation of development may be carried on in any room so long as absolutely no white light (even from the cracks beneath a door) is allowed access to it. An ordinary window may be used, but it must be covered with a frame glazed with ruby glass, and provided with an extra frame covered with “canary medium,” which is obtainable from any photographic dealer. We shall give a plan showing a convenient way of fitting the dark room sink, &c., but we do not advise the beginner to make use of day light (even when filtered through ruby glass) chiefly because the fluctuation from such a source of light often leads to a bewildering state of uncertainty. It is better to exclude all light from the room by covering the window with several layers of brown paper and covering all cracks with the same material. For effective illumination, then, we strongly advise the student to buy a well-made dark-room lantern; it would hardly be becoming to specially mention any particular make, although some years ago we used a lantern that has since been our ideal. As a guide to a beginner, we suggest the following features which should be possessed by a good dark room lantern. It should be large. It should consume either gas or paraffin. It should be provided with deep ruby glass, fitted in grooves and easily changeable. It should have extra grooves to permit of two panes of glass (red and yellow) being used, one over the otlier if desired. The flame should be regulated from outside the lantern. The chimney should be provided with “light traps” so that no white light can escape. The ventilation must be perfect. The price may range from 5s. to £1. All lanterns of this class are glazed with ruby glass, through which the flame is distinctly visible in its full glare. In our practice we always paste a sheet of orange-colored tissue paper over each pane of glass, which causes a pleasant diffusion of light, less trying to the eyes than a direct flame. The following features must be avoided in a lantern :