etching vs monoprint

etching

noun
  • The art of producing an image from a metal plate into which an image or text has been etched with acid. 

  • The image created by this process. 

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. 

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