First of all I would like to thank you for your answers in advance.Recently I got into after effects and now I am facing a problem I can't solve.What I want to do is remove the BLACK "sky" from a video and replace it with an image of another sky but I can't use keying because the sky is black. I've seen people using masks to do something similar but I don't really know how.Any ideas?
Try using a luma key, set it to key out darker, then adjust the threshold until you key out the black sky.
Johnny Cuevas, Editor
"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.