cupric acetate vs verdigris

cupric acetate

noun
  • Synonym of copper acetate 

verdigris

noun
  • A blue-green patina or rust that forms on copper-containing metals. 

  • The colour of this patina or material. 

verb
  • To cover, or coat, with verdigris. 

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