Book 3 — Red Lens Hinged to Flash Light for Dark-Room Use

A Ruby Cap Hinged over the Lens of an Ordinary Flash Light Is a Convenience for the Dark Room

Amateur photographers will find a red lens attachment for a hand flash light a useful arrangement for the dark room, when going in or out, and during the process of developing, especially in temporary quarters. To fit the device in place, measure the distance around the outside of the lens holder, and lay out this dimension on a strip of tin, or other metal, 1 in. wide, as shown. Then add ¹⁄₈ in. at each end, and an extra strip, which should be cut into ¹⁄₄-in. sections, along the whole length. A spring tab, midway along the top edge of the metal, is also made. Curl the piece to a cylindrical form and clinch the joint as detailed, and bend the notched tabs into place. Slip a piece of ruby glass into the cylinder and hold it against the notched tabs with a spring ring. Then solder a small hinge to the edge of the cylinder and to the lens holder on the flash light, so that the spring tab will snap into place. When a white light is wanted, the red-glass fitting is released, as shown.