perfecting vs polishing

perfecting

noun
  • The process of printing on both sides of the printed-on material during its single pass through the printing press. 

polishing

noun
  • The action of the verb to polish. 

  • An extract of partially milled rice. 

adj
  • That makes shiny or smooth. 

  • That refines. 

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