embrown vs umber

embrown

verb
  • To make (something) brown; to brown. 

  • To make (something) dark or dusky (“having a rather dark shade of colour”); to brown, to darken. 

  • To become or make dark or dusky; to brown, to darken. 

  • To become or make brown; to brown. 

umber

verb
  • To give a reddish-brown colour to. 

adj
  • Of a reddish brown colour, like that of the pigment. 

noun
  • A dusky brown African wading bird (Scopus umbretta) allied to the shoebill and herons; a hamerkop. 

  • A grayling. 

  • A brown clay, somewhat darker than ochre, which contains iron and manganese oxides. 

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