Diazo Process

diazo process

[dī′a·zō ‚präs·əs]
(organic chemistry)

Diazo Process


the production of images by means of photosensitive materials based on diazo compounds of the diazonium salt type. Diazonium salts are destroyed on exposure to light and form colored compounds (azo dyes) upon interaction with amines and phenols. The diazo process is used extensively for copying blueprints.


Katushev, Ia. M., and V. I. Sheberstov. Osnovy teorii fotograficheskikh protsessov, 2nd ed. Moscow, 1954. Chapter 18.
References in periodicals archive ?
Since the diazo process will recognize any opaque mark or change in drawing thickness, corrections to vellum or Mylar sheets using regular photocopy methods such as Scotch tape, White-out, etc.
Two duplication processes are commonly used to reproduce landscape drawings in large numbers: the diazo process and the photocopy process.
The Diazo process requires an ammonia-based chemical, which complicates its use within enclosed areas and makes cleanup in the field difficult.
The diazo process differs from traditional blueprinting, which creates a white image on a blue background (see page 122 of the November Sunset).