Matching Keyed Video to Background

[Mark Suszko]

I have had some success adding virtual lighting to a scene using Boris FX. In my case, it was a noontime outdoor shoot that had been shot with no fill, and I used a light inBoris to brighten up the face… it worked surprisingly well, and was not obvious.

If you are trying to color-correct these shots so all the CK greens match, that’s not necessary, or even desirable. I would key the actor first in each scene, then play with color-correcting his skin tones once he’s in an alpha channel layer.

If you mean you are taking the pre-keyed actors and trying to make them look like they were lit from the same sun angle as the fake replacement background… well, they should have lit them that way in the first place, but sometimes that can’t be helped.

I’d look into the trick I did with Boris for that, using whatever compositor you have. I’m not familiar with ColorFinesse, so I don’t know if it has similar controls in it. If nothing else, you can double-up and layer the video tracks, increase the brightness on one, then use a soft wipe or other matte to control where the revealed hotspot falls to simulate a keylight at the proper angle.

That’s all I can think of off the top of my head. Let us know how you eventually solved it.

[Kevin Herrin]

Thanks, I like the Boris idea. We may have Boris with FCP. I am trying to get post-key skin tones to look like they were shot on the location I have them on. So far adjusting the contrast and brightness has helped alot.
I’ll let you know.
Kevin

[Mark Suszko]

I’m sure you could do this with Shake or Combustion as well, and there’s an outside chance Motion can do it. There might even be a 10-dollar plug-in to handle it from DigitalHeaven. I LOVE those guys.

[Bob Cole]

I don’t understand the problem. Why should it matter what the color temp was for the foreground as long as you white balanced?

[Travis Fadler]

Check out Andrew Kramer’s tutorial on keying in After Effects. It contains some good tips for matching subjects with the background footage.

[Tony]

Bob,

The foreground is too warm in relationship to the background which is more blue. Even if the white balance was done properly under the two different lighting condition the two shots would have different looks in terms of warm or cold.

The two look out of place when combined together due to the differencs in color temperatures.

This is a common issue with green screen work and only color correction will help the blend them together.

Color finesse is fine to do the job just adjust your primary red and blue white gains along with gamma if needed.

Tony Salgdao

[Tim Kolb]

[Bob Cole] “I don’t understand the problem. Why should it matter what the color temp was for the foreground as long as you white balanced?”

Different palettes…very different. Not to mention angles and intensities, etc, etc. I always light with 5600 for greenscreen shots that I know I’ll be keying over exteriors…otherwise it’s pretty obvious.

Like the local weatherman when they replace his maps with some outdoor footage…in theory it’s all white balanced, but the weatherperson still is obviously separated.

TimK,

Kolb Productions,
Creative Cow Host,
Author/Trainer
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