best way to key out uneven white background?

[Bouncing Account needs new email address]

Did you try the Luminance Key?

[Todd Reid]

you said you have it pretty good, but some areas start affecting the talent…
back off the effect until the affect on the talent is gone. Use that as one matte. Then apply a second matte so remove the other color (hopefully you can draw one, all depends on your footage and where the affected areas are.

But bottom line is that you can add multiple mattes to a key, when done properly. Play with it.
concept would be the same in Motion, that’s where I’d do something like this. Seems a bit more able to do the fine tuning that sounds like is needed for this effect.

Todd Reid
Senior Editor
Digitized Media, Inc.

[Mark Suszko]

There’s a multi-point garbage matte you can apply. You could also try changing compositing mode to “multiply” over a cleaner white layer, before trying anything else.

Worst case, I have had very good luck using photoshop as a poor man’s roto system. (and if you know the history of PS you’re smiling at that phrase) Anyway, The idea is to export>using quicktime conversion>image sequence to a folder. I choose targas. In photoshop, open the first image in the folder, turn on the actions recorder, do the touch-up moves in there, save the recorded actions. You then can have PS batch the rest of the images in the stack all by itself with a couple clicks. I used this method a few months back on a job very similar to your problem, replacing the background where more traditional chroma or luma keying was just not working for me, and I didn’t have a way to work on it in a regular compositor.

The beauty is in how fast the rest of the stack processes once you get the “recipe” right for the first image. When the folder is done, you can just re-import to FCP, having first made sure the bin is set to give each imported still a duration of one frame. In practice this is a relatively smooth and seamless process to do. But if it’s too scary, you could just draw a more detailed mask in photoshop based on one frame, stick that in a layer on the FCP timeline, and composite thru it.

One of the neat things about FCP is how many diferent ways there are to do just about anything.

[Alan Okey]

[Dave LaRonde] “….and the elaborate process you describe is also a good argument for using a chroma key background to get the shot, and why chroma key exists in the first place.”

That’s also why it’s critical to know what you’re doing when setting up a chroma key shoot in the first place, to make sure that you don’t spend hours in post trying to pull a key from a crappy source plate. If only I had a dollar for every clueless low-budget producer who thinks that all you need to do is throw a green sheet on a wall, stick talent in front of it and shoot it with a DV camcorder…

Anything can be rotoscoped by a competent compositor. As you correctly state, the whole point of doing it right to begin with is to avoid doing roto. It sounds like the O.P. didn’t have the luxury of being present for preproduction meetings and now has to extract the talent from a white background that may never have been intended to be removed in the first place.

Any way you slice it, there’s no magic bullet to do this shot without at least some roto or garbage matting and/or combining multiple keys. Fortunately, Motion 3 now has spline-based roto masking tools.

Good luck!

[J. Tad newberry]

thanks to all of you for your input on this. this forum is SO phenomenal…and phenomenal because of so many people here willing to help and offer suggestions. i’m making some good headway on my crappy white background, and now looking at maybe getting the “Chroma Pop” screen that Digital Juice keeps advertising. have any of you guys used that? it looks to be nothing more than just a small flex-fill type toy with chroma-green on one side and chroma-blue on the other, and looks probably perfect for garbage matting behind a single talking head.

thanks again!

J. Tad Newberry
Big Ya Productions
http://www.bigya.tv

[J. Tad newberry]

It’s getting there fairly well. Thanks to the input from you guys, here is what is working pretty well if anyone is facing something similar:

1) i made sure i captured the BetaSP footage in 8 bit mode. Did a few tutorials on green screen and other keys.

2) In FCP, i first applied Color Smoothing to the clip. The tutorials said to do this, but i honestly don’t see much difference whether it is applied or not. I also tried the clip over the white BG in Composite Mode – Multiply. Didn’t see much change here.

3) Did an 8-point garbage matte to crop out the majority of the BG.

4) Applied a color key, sampling the BG near the talent.

5) Applied the Matte Choker.

Then i got the brilliant idea of trying to create my own holdout matte, and did this:

1) Original clip again, applied Color Smoothing.

2) Applied 8-point garbage matte.

3) Applied the Extract filter, and got it as close as possible to “done”, though several holes were still in it which i figured i would cover in Motion.

4) Rendered out this black and white file, brought it into Motion, and then started applying white shapes and keyframing them around to keep the talent completely covered. Saved this as my holdout matte.

5) Brought this into FCP, put in on layer 2, the normal clip on layer 3, and the BG on layer 1. Set composite mode of layer 3 to “Travel Matte- Luma”…and it looks purdy darned good!

BUT, i hereby promise to not do this again! I think I will buy the Chroma Pop…though it’s a wee bit on the little side, but should be fine for singular talking heads…

thanks again!

J. Tad Newberry
Big Ya Productions
http://www.bigya.tv

[J. Tad newberry]

p.s. i should’ve made it clear that the last 5 steps is a completely different way to do this than the first 5 steps, and the second 5 is turning out to be the cleanest way to do it, even though it will take longer with doing the keyframe steps in Motion. Oh well…

thanks again!

J. Tad Newberry
Big Ya Productions
http://www.bigya.tv

[Mark Suszko]

The chroma-pop is nice, but you’re really just paying extra for the wire flex frame, there’s nothing else “magical” about it that you couldn’t do as well with a roll of fabric and 2 light stands. Still, there’s a reason people pay extra for something at 7-11 than the local grocery store…