monochromatic vs soporific

monochromatic

adj
  • Plain, dull, lifeless. 

  • Having only one color, represented by differing hues and tints. For example shades in a black and white television. 

  • Perceptive of only one color; unable to distinguish colors; total color blindness. 

soporific

adj
  • Boring, dull. 

  • Tending to induce sleep. 

noun
  • Something boring or dull. 

  • Something inducing sleep, especially a drug. 

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