gravure vs photoengraving

gravure

noun
  • A type of intaglio printing process, in which an image is engraved onto a rotating copper cylinder. 

  • A style of Japanese softcore; glamour photography. 

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. 

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