diaglyph vs intaglio

diaglyph

noun
  • Glyptic art consisting of a sunken or depressed engraving or carving on a stone or gem. 

intaglio

noun
  • A design or piece of art which is engraved or etched into something. 

  • Any printing method in which the ink is laid upon the sunken parts of the printing form. 

verb
  • To engrave or etch using intaglio. 

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