Diazo Paper

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Diazo Paper


paper covered on one or, less frequently, both sides with a thin layer of a photosensitive substance made from diazo compounds. The paper is used in photocopying in diazotype photocopiers.

The process of producing a visual image on diazo paper has two steps. In the first step—exposure—an unstable positive image is formed in the photosensitive layer; the image consists of sections of undecomposed diazo compounds remaining under opaque areas of the original document. In the second step—developing—the undecomposed diazo compounds are converted into light-stable azo dyes of black, brown, red, orange, blue, or violet color.

Diazo paper is classified according to the composition of the photosensitive layer as single-component, two-component, or hot-process. Single-component paper contains only a diazo compound, which is developed by the wet process in aqueous solutions of azo compounds. Two-component paper contains diazo and azo compounds and is developed by the dry process, usually in ammonia vapors. Hot-process paper contains, in addition to diazo and azo components, compounds that when heated release substances required for developing. Diazo paper is produced mainly in rolls 20 to 100 m long and 0.3 to 1.2 m wide. In addition to diazo paper, diazo tracing paper is produced on a translucent paper base for use in preparing duplicates and intermediate originals.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
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The Ozalid copier used dyeline or diazo paper, known in German as Lichtpauspapier, which is "wet-strength paper with a light-sensitive layer to multiply text or drawings" (J.
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The objective of this study was to determine if the amount of accumulated photosynthetic photon flux density (PPFD) measured with a light meter is highly correlated with the number of exposed sheets of diazo paper under a variety of conditions.
Stacks of diazo paper (200SE Ozalid paper made by Film Paper Corporation Company of America) were constructed into booklets containing 20 sheets.
To develop relationships between diazo paper and accumulated and maximum PPFD, 75 petri dishes and a LI-COR 190SA quantum sensor, with a LI-COR 1000 data logger (LI-COR, Lincoln, Nebraska) were placed in full sunlight before 0800 on 21 June 1993.
To observe the rate of diazo paper exposure under constant light conditions, three sets of 36 petri dishes and a LI-COR 190SA quantum sensor with a LI-COR 1000 data logger were placed in a growth chamber.
The booklets of diazo paper were developed within 48 h of exposure to light by treating them with ammonia vapor in a plastic crisper (Friend 1961).