At what point do mixed Americans stop being considered black? ?

Question

For example Patti Austin, Rashida Jones (and many others) have a white skin, are white-passing but they are considered black in wikipedia and in popular culture.

Answer 1

When strangers assume they're white and still see them white despite getting a lecture on ancestry. Rashida Jones passes as fully white, Patti Austin looks light skinned black. Wentworth Miller passes as white even though he's light skinned black.

Answer 2

Never, they are called "Passers".

It is in slave trade 16th breeding (hexadecaroon) with a pure white. to start the chain. Some show after the 4th, called a quadroon.