Category: Lithography

INTRODUCTION Lithographic platemaking provides an ink-receptive positive image and an ink-resistant (desensitized) nonimage area on a plane surface. Many chemical mixtures are used to provide and develop the photo-sensitive ink-receptive image areas and render nonimage areas resistant to adherence of ink. Most metals have a natural tendency to be ink receptive and are to varying […]

Purpose.—The negatives or other film material received from the camera room are untrimmed, on larger material than page size, and cannot be used by the imposer until opaqued, trimmed to proper size, and combined with illustration material as necessary. The finishing tasks receive all of this photographic material and arrange it into uniform complete page-size […]

STATEMENT OF GENERAL FUNCTIONS OF OFFSET COPY PREPARATION Offset Copy Preparation, as a function in the Government Printing Office, serves as the inspector and judge for all reproducible materials used in lithographic production. This range of materials includes cold-type copy; reproduction proofs of metal composing; line art; photographs; manuscript copy for phototypesetting or metal composition; […]

The major requirement in reproducing copy containing various tones of gray is that such copy be changed photographically into a series of various size dots which, when printed with a black ink, will be interpreted by the eye to be various shades of gray. To accomplish this variety of dots, two types of halftone screens […]