monoprint vs rotogravure

monoprint

noun
  • A form of printing on paper from a glass sheet to which oil paint has been applied; monotype. 

verb
  • To print using this technique. 

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 monoprint and rotogravure occurred in a corpus of books? (source: Google Ngram Viewer )