I was noticing that in a lot of colorized versions of Betty Boop, her eyes are given color. I dislike this beyond words.
Since the finer aspects of human character are not translatable in any reasonable way, "life," or character must be communicated with exaggerated renditions of the grosser aspects of life. To wit, the massive eyes of most cartoon characters.
In most cartoons, the life of the character, truly the character of the character is found in the eyes. In cartoons more so than in real life, the eyes really are the window to the soul. Black & white characters were designed to be in black & white, and as such that's where their soul lies. If they were going to be drawn in color, they would have been drawn differently.
Take a look at Mickey Mouse.
As he evolved into color his structure also evolved. It's subtle, but substantial. Betty Boop has not evolved (if you forget that she was apparently once a dog), Nor do I think she should evolve. Her image is iconic at this point. Mickey's visage evolved to more or less its modern state by the 1940's. He's had decades to become iconic and evolve ever more finely.
I had a similar complaint of the new Scooby Doo cartoons. The characters never seemed right to me. They look sort of like the original characters I loved. They sound sort of like them. But there was still something seriously off about them. I didn't then and still don't see them as the original characters because the soul behind the drawing is different. It took me forever to place it. Then it hit me; they have whites in their eyes. The animators fucked with the eyes and fucked with the soul of the characters.
The new versions are technically good. Detailed. Express well. All around, they're good. They're different, though. Wrong, to my eye. The character has been fundamentally altered and as such I see them as different cartoons. Betty Boop is Betty Boop. Leave her as is. Who Framed Roger Rabbit nailed it, as you can see in this clip. She's up-to-date with advanced animation, but she's firmly in original character.