Any lens may be used for enlarging quarter-plate pictures to about 12 in. by 10 in. Theoretically, the best lens to use for the purpose is the one that has been employed to take the picture. Practically, the best lens is a portrait or rectilinear lens having a flat field and a large aperture. The focus should not be long, or the camera will require great extension. If a 6-in. focus portrait lens is used, the camera must be extended 24 in. and the lens be placed Sin. from the small negative. It is only necessary that the lens should sharply cover the small negative. Only quarter-plate portraits could be taken with a 6-in. lens. In some cases it may be best to fit the enlarging camera with a 6-in. rectilinear lens by a good maker (such as Ross, Dallmeyer, or Taylor), working at f/6. This could be used as it stood for ordinary work and enlarging ; whilst an occasional half-plate portrait could also be taken by using the front combination only, provided the extension of the camera is sufficient. If not, a conical front could be made to accommodate it. Every lens is supplied with a flange, which only needs screwing to the opening in the camera front. As daylight enlargements are best, it is unnecessary to have a camera for enlarging.

Place the small negative in a carrier in the dark slide with both shutters drawn out, insert the slide in the camera, and place it close against the window frame, with the lens, covered with a cap of ruby glass, pointing into the room. The whole of the window, except a small opening to admit light to the slide, must be blocked out and the room rendered thoroughly dark. Outside the window must be a white reflector, at least four times the size of the negative, fixed at an angle of 450 with the negative, and receiving light from the sky. On placing a sheet of white paper on an upright easel and moving gradually from the lens, a position will be found (viz. 24 in.) where a sharp enlarged image of the small negative is shown on the paper. It is merely necessary then to pin a sheet of bromide paper on the easel and expose. Daylight exposures are constantly varying, and call for some experience, but better gradation is obtained.