| 摘要 |
<p>928,203. Plate for image production by engraving. FAIRCHILD CAMERA & INSTRUMENT CORPORATION. Aug. 4, 1961 [Aug. 11, 1960], No. 28439/61. Class 98 (2). A uniformly finished-surface sheet of deformable transparent plastic material has one surface impregnated with a material having a low transmittance to ultra-violet light but otherwise retaining the original finished-surface character. The impregnating material may be a dye, or if colourless may have added dye for visibility. Engraving may be effected through such surface by the machines described in Specifications 692,349 and 692,400 to produce a screened image, of the type shown in Specification 878,474, which may be used directly as a letterpress printing plate or may be exposed on to photo-actinic paper as for offset plate production. An example describes production of the plate by application of a solution of oil yellow in methyl alcohol to a skived sheet of cellulose nitrate having its surface finished by polishing under heat and pressure and drying, and numerous other plastic sheets, impregnating materials and mutual solvents therefor are listed. Specification 557,352 also is referred to.</p> |
