photoengraving vs tracing

photoengraving

noun
  • A process of transferring a photographic image onto a plate which is then etched and printed. 

  • A plate or reproduction made using this process. 

tracing

noun
  • The reproduction of an image made by copying it through translucent paper. 

  • A record in the form of a graph made by a device such as a seismograph. 

  • The process of finding something that is lost by studying evidence. 

  • A regular path or track; a course. 

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