a. Drawings. Drawing or sketching is a universal language used to convey all necessary information to the individual who will fabricate or assemble an object. Prints are also used to illustrate how various equipment is operated, maintained, repaired, or lubricated. The original drawings for prints are made either by directly drawing or tracing a drawing on a translucent tracing paper or cloth using waterproof (India) ink or a special pencil. The original drawing is referred to as a tracing or master copy.
b. Reproduction Methods. Various methods of reproduction have been developed which will produce prints of different colors from the master copy.
(1) One of the first processes devised to reproduce a tracing produced white lines on a blue background, hence the term “blueprints”.(2) A patented paper identified as “BW” paper produces prints with black lines on a white background.
(3) The ammonia process, or “Ozalids”, produces prints with either black, blue, or maroon lines on a white background.
(4) Vandyke paper produces a white line on a dark brown background.
(5) Other reproduction methods are the mimeograph machine, ditto machine, and photostatic process.