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Screen-Plate Patents 497
R. de Bercegol105 proposed to use a resist of soft consistency, such as wax, tallow, etc., and coat celluloid with one dye, dissolved in alcohol, and after this had been allowed to act, it was washed off then coated with the resist and lines ruled through it and the superficial color film, thus laying bare the colorless celluloid, which was then stained up with the second color also dissolved in alcohol. The operations were repeated for the third color, with the ruling at right angles.
R. Nishimo106 patented a rather curious process in which he claimed that the various colors produced in the image a distribution of the grains varying with the wave-length, but the effect was masked by the silver grains superposed in a haphazard manner. The solution of these grains would leave an image in colors. K. Schinzel107 patented a screen in which the elements were formed by derivatives or other conversion products of lycopodium or other pollens. E. Scherpel108 proposed to apply a colorless substratum to a support, spray on a resist, then bathe in a solution of a blue dye, which adhered between the particles of the resist. This latter was then removed and a red dye applied to those places where the resist had been. A yellow dye was then sprayed on, which formed green and orange spots on the blue and red dyes, thus giving a four-color screen. F. May109 patented the use of a fatty resist and ruling this while hot. The dyes were to be fixed with ferric chloride, aluminum acetate or formaldehyde.
Woven and Allied Screen-Plates. — J. Joly110 suggested the use of silk fibers, either natural or artificial, dyed to the required colors, applied side by side to a tacky surface. He further disclosed the weaving of the filaments into a fabric to be applied to the support, the colored threads forming the warp and the weft consisting only of a sufficient number of colorless threads to cause the threads of the warp to retain their relative positions until secured on the support.
R. Berthon and J. Gambs111 would use woven fabric, or linear filaments alternately colored in the proper colors might be stuck to one another or imbedded in a homogeneous material. The latter means permitted not only colored negatives being obtained, but also positives by printing from the negatives. The threads were to be placed parallel to the longer side of the plates for the negatives ; this arrangement automatically assuring the superposition of the dyes of the same color at the point of intersection of the filaments. The refraction of the light in the monochrome filaments, when each filament was exposed within the exact limits set by those of complementary colors, caused the silver to be affected over the whole length exposed. The filaments of single thread or ply were received on conical rollers, which by rotating and sliding the threads along the generating line, brought them into contact; and this was made more perfect by moistening them with a viscous mass and causing them to travel over a polished cylinder, the tangential velocity of which was greater than the velocity of the threads. Capillarity then ensured contact, without overlapping.
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