Ozalid

n. printing process in which a drawing or writing is transferred to a sensitized paper and is developed using ammonia vapor

The Ozalid Process In printing, ozalid process is the name for a process of printing positive images on paper from patterns on film or other translucent media. It is akin to creating a photogram, using chemically treated paper. A tranparent film with the pattern to be printed is placed on a diazo compound coated paper. This sandwich is exposed to ultraviolet light. After a 15 sec to 5 min exposure, ammonia vapour is used to develop the film image on to the paper. Its main use was for making copies of electrical, mechanical and civil engineering drawings. It is still used widely in developing countries. It is also used for proofing, as it produces an image very close to the finished work.
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n. ozalid, printing process in which a drawing or writing is transferred to a sensitized paper and is developed using ammonia vapor