emulsion vs tempera

emulsion

noun
  • The coating of photosensitive silver halide grains in a thin gelatine layer on a photographic film. 

  • A stable suspension of small droplets of one liquid in another with which it is immiscible. 

  • A colloid in which both phases are liquid. 

verb
  • To paint with emulsion paint. 

tempera

noun
  • A painting done in this medium. 

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

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