| 摘要 |
587,957. Photographic stencils. KODAK, Ltd., and GRESHAM, D. C. Oct. 27, 1944, No. 20992. [Class 98 (ii)] A method of forming a gauze type printing screen comprises forming a latent image in a silver salt emulsion layer on a support, developing the latent image, and etch-bleaching to a gelatine relief image which is caused to adhere to a gauze whereafter the support is removed leaving the relief image on the gauze. A stripping layer may be provided between the emulsion and support or a stripping solution may be used. In an example, a negative image on a plate is developed in a hydroquinone caustic developer and etch-bleached in a solution containing cupric chloride, acetic acid and hydrogen peroxide. The plate is then rinsed and blackened in a solution containing thiocarbamide and sodium hydroxide and then brought into contact with a silk screen previously soaked, first in a sodium hypochlorite solution and then in a sodium silicate solution. After drying, sodium fluoride solution is applied to the screen and then hydrochloric acid. The screen and relief image can then be lifted off the glass plate. Specification 278,647, [Class 98 (ii)], is referred to. |
