So I'm basically a noob user of after effects. I've done a few test videos and pics of lightsabers and what not so I somewhat know my around AE for these purposes. As you can see in the attached photo the child's green lightsaber color is distorted at the bottom from his blue shirt. Is there anyway to fix this?
If you are trying to simulate the way actual light would appear it would blend with the background color as your light sabers do. Setting the project to 32 bit and using the add or screen blend mode is the best way to simulate the natural behavior of light. If there was no influence by the background your composite would look fake.