The Recording of Spectra on Sheet Film Our experience in the problems of adapting the photographic plate holder of a spectrograph to enable sheet film to be used instead of glass plates may prove useful to readers. Film is cheaper than plates, readily cut to any size and, unlike some plates, is commonly available. We have, for example, used Kodak Tri-X film, cut to various sizes, t o cover the range 220-650 nm. The procedure described below applies t o any film, including 35-mm roll. First, a thin (-0.5 mm) brass plate is cut to the plate holder size and one side is completely covered with strips of double sided tape (e.g., Scotch@tape). A piece of suitable heavy duty plastic material (transparent plastic for covering books is ideal) having one sticky side is cut to size, and its plain side pressed down onto the tape on the brass plate. In the darkroom, a piece of p r e c u t photographic film is gently pressed into position on the sticky surface of the brass plate, and the complete assembly is mounted in the plate holder, just as a glass plate would he. After exposure, the film can he peeled away and developed normally. Up t o 50 pieces of film can be used before the sticky plastic backing needs to be replaced. The described procedure ensures that the complete area of the photographic film is located precisely in the focal plane, with no bulging, and that all parts of the spectrum are in focus.
A. G. Briggs and R. E. Simmons Loughborough University of Technology Leicestershire. LEI1 3TU. England
Volume 59
Number 4
A ~ r i 1982 l
343
