i figured out how. say i want to change the color of the sky to already corrected/graded footage. i duplicated the track and masked out the sky. i left apply to fx off since i just want the sky overlaying in the other track. i brought some clouds back into the shot. could someone explain to me the difference in opacity and the slider on the video track? do the do they same thing? also, i noticed the order of the video tracks has an effect on the overlay. my masked clouds have to be on top for them to appear. is this the proper way of doing this or can i change the composition settings for each track? and how does the parent and child buttons effect the overlay?