American illustrator Al Dorne (1906-1965) painted this ad showing mother who is exhausted from hosting a birthday party being perked up by the thought of some Maxwell House coffee.
Dorne created the illustration with layers of transparent inks. In American Artist magazine, the Higgins ink company ran another ad sharing Dorne's method: "In working with waterproof drawing inks, Mr. Dorne finds that the tones never become muddy, no matter how many washes are used."
True, but it begs the question: How was Dorne able to change her from a brunette to a blonde and turn her head slightly in the published illustration (see first image in the post). Did he cover the original rendering with a layer of opaque priming? Or did he mortise in the correction with another piece of board? I'll bet it's the latter, and that he covered the mortise line with the addition of a choker.
In the days before Photoshop, such changes were a pain in the royal butt.
Wikipedia on Al Dorne
Book: Albert Dorne: Master Illustrator by David Apatoff, author of "Illustration Art" blog.
Higgins still makes black waterproof ink or you can get a set of colors.