Hello, I am attempting to do the scribble light effect in AE but when I access the layer panel and toggle ON Paint on Transparent it hides my background footage and goes black. I can still paint but I only see the brush strokes. I can see the footage again when I set the view to none, but as soon as I make a brushstroke it goes back to paint and my footage turns black again. I am a beginner so its probably a simple issue, but I cannot find a fix for it anywhere.
This is expected behavior. You are asking AE to erase all existing layer content in favor of your painted stuff. You may need to apply your paint stuff to a separate layer on top of the actual layer to get the result you want.