blotter vs sketchbook

blotter

noun
  • A piece of blotting paper in a pad as a piece of desk furniture. 

  • A register of the related events made in the form of the list of times and brief descriptions. 

  • A daily register of arrests and other events in a police station. 

  • A portion of blotter acid. 

sketchbook

noun
  • A book or pad with blank pages for sketching; a sketch pad. 

  • A book of printed sketches. 

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