>>9668438Painting joints usually introduces its own set of problems, like fit issues where the paint has added enough thickness to the joint to make it difficult to fit into the piece anymore. It also is notorious for flaking off as soon as you move the joint, because it's rubbing against the insides of the limbs. This is how you get stuff like this, where the plastic color peeks out at you.
So far, I don't think any companies have come up with any truly smart solutions for this, at least as far as I know. For designs where the color is split vertically instead, we've seen clever things like elbow joint halves cast in two different colors. But even attention to detail like that is relatively rare.
