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A diazo copier, whiteprint copier or blue-line copier, is a type of heliographic copier used in the world of Reprography for making contact prints on paper from original drawings made on Vellum or other transparent or translucent material using the diazotype technology. The different names were given, due to the nature of the process, which consists in exposing to an ultraviolet light a previously sensitized paper with a component called diazo, and finally developing it in a bath (a solution of ammonia in water) which converts the parts not exposed to light, to a dark blue colour (blue-line) on an almost white background. == History == The light sensitivity of certain chemicals used in this process, it was already known in the 1890s and several related printing processes were patented at that time. The process of diazotype replaced the cyanotype process for reproduction of drawings of architectural and engineering blueprints, because the technique was simpler and made use of less toxic chemicals.〔 (Blueprints replaced by whiteprints )〕 In the "argot" of engineers, architects and designers, no matter they where either blue or white, the resulting plan copies were traditionally called blueprints, name derived from the blue background color of the cyanotype technique, which was the previous process for obtaining blueprints. When the diazo based compounds changed the background color to white, in technical environments, -by tradition-, the name for copies of technical drawings remained Blueprint , although in English-speaking countries, it was intended, without much success, to change the name from '' Blueprint '' to '' Whiteprint ''. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Diazo copier」の詳細全文を読む スポンサード リンク
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