Here is some additional information on photolettering techniques from The Inland Printer. The techniques have already been discussed in a previous post on information in The American Printer. There are no accompanying illustrations.
January 1940, p. 72 A short announcement of Photo-ray, a “clever-new process invented by Edwin W. Krauter” in which transparent pattern letters, made from original alphabets provided by “master letterers”, are assembled by hand from a case and then placed in a line (which can be angled or curved if so desired) which is photographed. The quality of the Photo-ray process is due to superior hand lettering. “Trick” camera work (eg. condensing, expanding, sloping, etc.) is also possible. The company behind Photo-ray is Lettering, Inc. in Chicago.
February 1940, p. 70 “Bernhard Photo-magnetic Lettering” now being used by the Composing Room, Inc. in New York. [The Composing Room was run by Eli Cantor and Dr. Robert Leslie. It published PM and AD magazines.]