blackness vs tar baby

blackness

noun
  • The experiences and culture of African-American people. 

  • The state of being of African descent. 

  • The quality of being evil or dismal. 

  • The state or quality of being black in colour. 

tar baby

noun
  • A black person. 

  • A difficult, abstract problem that worsens as one attempts to handle it; a "sticky" situation, especially one where attempts to make it better only make it worse. 

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