pictorialization vs symbolization

pictorialization

noun
  • The process or result of pictorializing. 

symbolization

noun
  • The act of symbolizing; the use of symbols to represent things, or the investing of things with a symbolic meaning. 

  • The unconscious mental representation of one thing by another. 

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