blotter acid vs mordant

blotter acid

noun
  • Blotter paper impregnated with the drug LSD, to be taken orally. 

mordant

noun
  • Any corrosive substance used in etching. 

  • A glutinous size used as a ground for gilding, to make the gold leaf adhere. 

  • Any substance used to facilitate the fixing of a dye to a fibre; usually a metallic compound which reacts with the dye using chelation. 

verb
  • To subject to the action of, or imbue with, a mordant. 

adj
  • Serving to fix a dye to a fibre. 

  • Having or showing a sharp or critical quality 

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