There's a ton of cartoons from the era clearly blackface.

However, to your point, even recent photographs in color and black and white depict the tonal contrast one could imagine inspiring the cartoon character in question:

https://qph.fs.quoracdn.net/main-qimg-3e50441087256791f079ff...

https://get.pxhere.com/photo/black-and-white-people-white-ph...

Until you get to the name Inki... tips their hand a bit.