I want to creat an effect in a scene where there are 3 characters. Every character is wearing a different coloured shirt. I want to make every thing in the scene black & white, keeping the colour of their shirts intact.
Ok, problem with the Plesantville effect is, once you single out one color, you can't single out a second color on the same clip.
Here's what I had to do. Make three different clip. Do the plesantville effect as per that tutorial on each, each clip being a different color.
Then I put a mask on each as close to each character as I could comfortably do it. In part to composite them all together. Second, to mask out objects that were the same color in the shot.
Place all that on top of your full original desaturated for BW.
That was regular Mini-DV tape recording NTSC-DV. I think it was a DVX100. I was sent a QT file to work with. But that is NOT anything but original DVX100 DV footage saved to a QT file. The original is much longer, I just put up a few seconds to get the idea across.
If you see the full clip, there's lots of bad spots. It would take tons more work to clean up. If you were in the DVCPRO-HD color space, then yes, it'd be much easier to do.
I'd also use something a tad better than FCP's color corrector. This clip was done with it, I've done others like it with it, but it's a lot of time to do! I spent a full week doing nothing but keyframing 50 point garbage mattes around those girls and the guy walking in front of them! It's like 5 or 6 layers of video I had to use. And all of the same clip, which made my head swim trying to keep track. I learned a lot about media managment on that job! And that was a few years ago, too.
Had I used Shake, it would have been much faster and easier. But, I'm just getting into Shake, so I'll probably use that for awhile.
Don't remember the name, but there's supposed to be a really killer matte plug-in to do this stuff for Motion that's really great. Oh, I remember now, DV Matte Blast. Supposed to be really great. Made by the DV Garage folks. I may use that next time.