monochromatic vs monochromous

monochromatic

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

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

  • Plain, dull, lifeless. 

monochromous

adj
  • Synonym of monochrome 

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