system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why on old cartoons, did a scenery object look brighter if the characters were going to interact with it? Why would the quality differ regardless?
gpt
They were being drawn in different layers.

Old cartoons were literally drawn on clear plastic sheets like you'd get on an overhead projector.  Character's movements therefore had to be drawn and redrawn for each frame.  The background didn't.  It would stay the same for multiple shots.  These different layers would be stacked on top of each other and a picture.would be taken.  Then, the character pictures would be swapped out for the next frame.  Maybe the background would be moved a bit too.  If an object was going to move, it would have to be on a separate layer from the background.