Keylight (CS3) has blocked-grainy output


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Keylight (CS3) has blocked-grainy output
by Randy McWilson on Feb 14, 2008 at 11:40:55 pm

Keylight in the new CS3 creates strange and random noise inside the matte when rendered, even though the screen matte is showing pure white inside our subject.

When we render out for playback, a jittery, grainy, blocky pattern appears on our subject.

This occurs whether we use a choker or not.

Randy

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Re: Keylight (CS3) has blocked-grainy output
by Dave LaRonde on Feb 14, 2008 at 11:59:49 pm

Yup, that'll happen with Keylight if the video level of the keying color is too high. If you're looking at a scope, Keylight likes the color to come in about 40-45 IRE units, and I'd guess yours is at about 60 units or more.

The way I work around the problem is to do a 2-step key. I start with a good key, which you already have; please note I didn't say a good-LOOKING key... right now, yours is ugly. Then I duplicate the layer.

On the bottom layer, I reset the effect and play with it until I get spill removal, but the background goes gray in Keylight's final output setting. It takes a bit to get to that point, but then it suddenly gets easy. I use the layer above it -- the good key -- as an alpha matte, and Poof! I have a good key AND spill suppression.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV

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Re: Keylight (CS3) has blocked-grainy output
by Randy McWilson on Feb 15, 2008 at 8:05:41 pm

Dave:

I also found another (similar) workaround.

I duplicate my layer. Take the top layer and add Keylight and then go into "SCREEN MATTE" instead of "Final"

I tweak to make the key clean, and pure white inside of the subject.

I then select the lower layer and use a Luma track matte (the important thing here is to leave Keylight in the layer above on "screen matte")

Works good---doesnt have the added benefit of edge color correction though.

Eternity...don't miss it for the world.

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Re: Keylight (CS3) has blocked-grainy output
by Pat Jaeger on Feb 17, 2008 at 2:18:22 am

Hi, what tools would i use to remove the spill from the bottom layer as you describe?

Thanks,
Pat

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Re: Keylight (CS3) has blocked-grainy output
by april henderson on Feb 17, 2008 at 3:36:53 am

Yes..I would love to get a little more detail on this one too. It means a lot to me. In the second Keylight layer which we have reset. How exactly would we remove that spill?
Should we just use the Edge Color Correction tools??

thank you!

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