Stencil screens can be made as follows: Prepare a water solution containing about 11%-12% "Elvanol" 52-22, 1.0% of a bichromate such as sodium bichromate, and enough light-fast dye or pigment to give the desired contrast in color. Dark blue or green rubber stamp pad ink may be used. Filter through a cloth or fine mesh screen and allow to stand overnight in order to free the solution from air bubbles. Pour the solution into a shallow tray slightly larger than the screen to be coated. hold the screen in a horizontal position and dip into the solution sufficiently to coat the entire outside surface, exercising care to prevent the solution from seeping through the screen. Then attach the screen to a whirling machine and whirl at 300-400 r.p.m. for one or two minutes to insure uniform distribution. Place the screen in a horizontal position in a well-ventilated darkroom and dry at about 70-80'F. When dry, expose to ultraviolet light through a photographic positive of the design. The time of exposure will, of course
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