| 摘要 |
522,782. Drawing material. SANDERS, L. S. Dec. 2, 1938, No. 35212. Convention date, Dec. 4, 1937. Drawings to Specification. [Class II] [Also in Group XX] Drawing material for use in preparing drawings to be photographically reproduced comprises a base sheet carrying a film of material capable of chemical development and a transparent or translucent water - insoluble coating protecting the film from the action of the developer and covering selected portions of the film. The coating may cover the film with the exception of a multiplicity of uniformly spaced dots. The time of action of the developer may be locally varied to give different tones. The base may be paper and the film gelatin, albumin, casein, or glue. The varnish coating may be applied to the film by a printing plate having small square openings. The sensitizer may be ammonium molybdate; a mercury compound ; zinc di - n - butyl - dithiocarbonate; dimethylglyoxine ; a tellurous compound ; a mercury, lead, copper, nickel, cobalt, bismuth, or tin compound; or a silver compound. The corresponding developer is respectively stannous chloride ; thiourea ; a copper compound ; a nickel compound ; stannous chloride ; a soluble sulphide; or an alkali solution, reducing agent, or soluble sulphide. The. sensitizer and developer are interchangeable. |
