draftsmanship vs portraiture

draftsmanship

noun
  • the skill of drawing 

  • the art or craft of a draftsman 

portraiture

noun
  • The art of painting or photographing portraits. 

  • A portrait (or portraits considered as a group). 

  • A portrait; a likeness; a painted resemblance; hence, that which is copied from some example or model. 

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