Well, that IS confusing.
First of all, I'm assuming you don't have After Effects - this would be much easier in AE.
Here's what I would do in PPro - create a 'title' in the shape of the sky you want to cut out. You will have to use multiple shapes in the title tool to accomplish this and go around the tree you want to keep.
Put this 'title' on the layer above your footage and use it as a track matte for your footage. Then, put your blue gradient layer below your footage layer and adjust colors to taste, or replace the sky completely with a different clip.
If there is any movement on your footage, it is going to be very difficult to track and make this method of matting look decent - good luck.
Hope this helps.
I actually DO have AE, I just thought that this can be accomplished this way. Actually I pretty much figured that the way i was describing above would not be optimal for the effect I'm looking for color wise BUT I wanted to ask anyway so i at least know how to properly have one matte cancel out another. I tookt he clip into AE and was working with Colorista 2 which is much better for this like you said, but I'm having an issue with a part of the sky I'm trying to affect ends up being in the same part fo the color spectrum as the highlights on someone's shoulder as they walk into frame, so I'm trying to figure out how to properly use a matte in AE to have the grading not affect the shirt.
Is there a reason you don't want to matte out the entire sky? That would be relatively easy in AE. I would suggest Andrew Kramer's (Video Copilot) very first tutorial - Basic Sky Replacement. http://www.videocopilot.net/tutorials/basic_sky_replacement/
Alternately, you could put your CC on an adjustment layer in AE, then create a mask on the adjustment layer so it does not effect the subject's shoulder.....
Super tutorial! I was wondering if something like could be done but had no idea exactly what to call it to search for it. Thanks a bunch.
Yeah, Andrew Kramer is an AE genius. Don't miss all his other great tutorials, they've taught me a lot!