gravure vs rotogravure

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. 

rotogravure

noun
  • A printing process by which the paper is rolled through intaglio cylinders. 

  • A print made by such a method. 

  • A portion of a printed work produced by this method. 

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