artist's impression vs photography

artist's impression

noun
  • A sketch or drawing of someone or something, produced when it is not possible to take a photograph. 

photography

noun
  • The art and technology of producing images on photosensitive surfaces, and its digital counterpart. 

  • The occupation of taking (and often printing) photographs. 

How often have the words artist's impression and photography occurred in a corpus of books? (source: Google Ngram Viewer )