User:Worrella/sandbox

Dual Spectrum technology was the successor to the Thermo-fax. It also involved a receptor sheet ("intermediate") which was exposed to light (not infrared ... standard light bulbs were used in the machine in the photo) and developed by matching the intermediate to a sheet of treated paper. It differed from Thermo-fax in that respect; the resulting copy appeared to be on "plain" paper. The photo in the article is actually not a Thermo-fax, its the Model "051" Dual Spectrum machine, which was introduced by Graphic Systems Wholesale in 1970 or 1971.