[Darby Edelen]

[Travis Dao] ” My current work-around is to adjust the key so there are no white artifacts (but i lose some of his face) then do a separate key on his head and mask that over.”

Sounds workable.

Another suggestion is to consider the keying process as it’s own discrete process the only purpose of which is to get a good alpha. It doesn’t matter if the guy looks purple, orange or yellow at the end of that process. You can always go back to the original RGB, clean up the spill and matte it with the keyed alpha.

Darby Edelen

[Darby Edelen]

[Travis Dao] “How would you go about keying someone in front of two shades of green?”

Well, that definitely complicates things 🙂 I’d start by trying to treat them separately. Duplicate the footage, create a mask for each shade of the screen with some overlap in the center then key each instance separately. The overlapping area will be the hardest to manage. To get a clean edge it might require some fairly gnarly roto work.

Darby Edelen

[Darby Edelen]

Reset your values to default, except the screen color, and let us know if you still see it. If not then it’s one of the screen settings, screen pre-blur maybe, otherwise it looks more like a footage problem.

Darby Edelen

[Darby Edelen]

Lower your Screen Despot Black value. This runs a Median (smoothing) operation on parts of the matte. What you’re seeing is the smoothing of the sharp angles in the man’s pits/groin.

Darby Edelen

[Darby Edelen]

[Kunal Puri] “If you’d like to help out this hapless soul a wee more, and when you have a little time, could you help me get my head around the trig involved. I’m pretty sure (with my kind of luck) I’m going to need it sooner or later. Cheers”

Well, it takes some simple trig as well as an understanding of what the ‘Zoom’ property on the camera represents 🙂 So here’s an image to help explain.

Note that once you follow the simple(r) process at the top of the image, you could just scrub the ‘zoom’ values of your cameras to get quite close to the correct field of view. The rest of the image goes into the trig which could be used to create an expression on a camera’s zoom property.

Darby Edelen

[Darby Edelen]

It looks like you’ll need to use a mask to holdout his head due to the similar color of the helmet. I’d still use a luminance based matte for the majority of the replacement.

Darby Edelen

[Darby Edelen]

There is a drop down that usually defaults to something like Final Result (my wording may be off there), try changing that to Intermediate Result (again, might be off there). This is the same key as the Final Result with no color correction/despill applied.

An image might help diagnose this, a project file with a still problematic frame might help even more 🙂

Also if you’re viewing at anything but Full resolution in the Comp Viewer you should see if this also appears at Full resolution.

Darby Edelen

[Darby Edelen]

[Darby Edelen] ” One possible issue is that you’re viewing through “Camera 1” in your composition viewer while the Render Queue will use the “Active Camera” view at render time.

If you want to use “Camera 1″ make sure it is the topmost camera in your timeline.”

So the issue is related to what I’ve said here but slightly different. Your Camera 1 layer has its out point trimmed to 30 seconds. When that camera layer is no longer active the ‘Active Camera’ reverts to the default position. You need to extend the Camera 1 layer out to the end of the timeline.

Darby Edelen

[Darby Edelen]

Hard to say exactly but usually when Keylight goes wrong it has something to do with the despill color correction. You can disable this part of the pipeline by using the ‘Intermediate Result’ instead of the ‘Final Result.’ Try that and see if the problem goes away.

If it does you’ll need to despill your footage by another method. I like to duplicate the footage, use the Channel Mixer effect to clamp the Green values at a combination of the Red & Blue values (start at 50% Red and 50% Blue) and set this to the ‘Darken’ blend mode above the keyed footage. That’s always given me a great result.

You may also try toggling the ‘Unpremultiply Result’ checkbox to see what you get.

Darby Edelen

[Darby Edelen]

One possible issue is that you’re viewing through “Camera 1” in your composition viewer while the Render Queue will use the “Active Camera” view at render time.

If you want to use “Camera 1” make sure it is the topmost camera in your timeline.

Darby Edelen