Chroma keying is removing person's face
by Simon Taylor
on
Oct 24, 2008 at 3:37:56 pm
Hi there,
I've filmed a shot of someone in front of a mirror with the mirror reflecting a red screen (i didn't have green). When I try to remove the red in AE if i remove it all I lose some of his face, if I dont remove it all I get red speckles and boarders left over. I'm pretty new to this so dont really know what else to do. I'm using a combination of chroma key and keylight. Is there a way of doing this without have to mask around him for the whole shot?
Re: Chroma keying is removing person's face by Dave LaRonde on Oct 24, 2008 at 4:00:30 pm
Here's a little basic information: there is more red in a typical human face than any other color.
Considering that, it's a darned good-looking key. Frankly, I'm surprised.
Even so, just as you would think twice about putting Kermit The Frog on a green screen, you might want to re-think your red background for better success.
The jagged edges you're getting my not be due to the color, but to your video. May I assume you're shooting on DV? It's notoriously tough to key DV.
I would work with adding a little edge blur in keylight. If you find the results unsatisfactory, I would re-shoot using an HDV camera. I don't normally recommend HDV AT ALL, but it could prove handy in a standard-definition situation. You can hide a lot of HDV's many flaws in SD.
Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA
Re: Chroma keying is removing person's face by Simon Taylor on Oct 24, 2008 at 5:17:12 pm
I filmed it using HDV (Canon HV30). I'll try your suggestions, thanks. If he was around still to reshoot I'd buy a green screen and do it. I'll see how I get on, don't really want to have to roto! Although I've heard you can use the motion tracker somehow to help speed it up?
Re: Chroma keying is removing person's face by Darby Edelen on Oct 24, 2008 at 5:32:11 pm
That's actually a much better key than I was expecting. My suggestion would be to use what you have as a 'core matte' since the image is pretty good aside from the edges. Simply choke the matte in on the key you already have for this, don't worry if the edges get bad.
Then key again and try to get the edges looking good, ignoring the fact that holes will appear in your talent's face. Place this layer above the core matte to fill in the holes and you should have better results.
