Nowadays we can see talk show panels composed of people who have to tell people they're black because they're pale, don't look like the "black" archetype, and therefore miss out on all the racism they're entitled to. If someone can be "black" by proclamation, then the term is as meaningless now as it was in the 1920s.

She was his
She would take his children
Black and white
Right to her own breast
There were times
When he could mix
With ordinary white company
And if the subject never came up
No one would notice
He had what they call passing complexion
He had what they call passing complexion
He had what they call passing complexion
He had what they call passing complexion
He'd been white, he'd been black
They asked him, black like that?
Yeah!

Steve Albini: I couldn't tell you exactly... I could tell you what specific things in it are. There's the line, "She would take his children, black and white, to her own breasts" -- there was an Amelia Jackson interview on the radio that I listened to once, and she was talking about how her mother would nurse these white parents' children, literally wet nurse them.

So here's this woman who is good enough to take their babies and raise them and feed them off her breast, but she wasn't good enough to sit in their living room.

There was basically a whole third class of citizens who were black people who were pale enough to be accepted into gentile company if they were entertainers, if they were businessmen in town or something like that. They had passing complexion -- they weren't so dark that people had to think of them as black people, they could sort of construe in their mind that they were white people if it were convenient. If there was some reason to, they could think of them as white people.

There were only two divisions in society -- the rich, upper-crust white class or just another darkie, and the divisions were so obvious, so they all tried to fit into white, gentile society. That's where the whole industry developed for hair straightening and skin lightening. Like Porcelana Fading Cream was originally developed to lighten negro skin.