photoengraving vs photostat

photoengraving

noun
  • A process of transferring a photographic image onto a plate which is then etched and printed. 

  • A plate or reproduction made using this process. 

photostat

noun
  • A photocopy made using a photocopier. 

  • Positive (black on white) or negative (white on black) reproduction of printed matter or artwork made on a photostat machine, which uses photographic paper instead of a transparent negative, and uses a prism to render the paper negative readable instead of reversed. 

verb
  • To make such a photocopy of. 

How often have the words photoengraving and photostat occurred in a corpus of books? (source: Google Ngram Viewer )