pigment vs tempera

pigment

noun
  • A dry colorant, usually an insoluble powder 

  • Any color in plant or animal cells 

verb
  • To add color or pigment to something. 

tempera

noun
  • A medium used to bind pigments in painting, as well as the associated artistic techniques. 

  • A painting done in this medium. 

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