BMCC Raw Chroma key workflow

Question: I have recently filmed some subjects on greenscreen, shot on a bmcc in raw film mode. I need to color them?? to make them keyable in AE. (AE applies a rec 709 on import, and is a bit doggy so it seems I should use resolve to convert them to another format).

What is a good workflow? Do I do a "near final" color pass in resolve to make it more keyable in AE, and out put a prores or tiff sequence from resolve for AE import? Any suggestions? The flat nature of the footage makes it a bear to key in AE.....

DPX would probably be the best format for AE, so you can keep maximum data.

You'll get better results if you grade one version of the footage to pull the matte in AE, and another as your "beauty pass" to use in your composite.

The keying pass should have a nice strong green that looks fairly pure on your scopes, and should be about one stop darker than the foreground talent. Watch the edges of the talent, so you don't bleed the green over the edges.

In AE, output the matte (B&W) and use it as an alpha channel in your composite, using the beauty pass footage for the RGB.

If you use Keylight in AE, it will work much better if you build a procedural core and outer matte. Here's a video of Alex Lindsay late of ILM showing how to do it with Keylight in Shake.

DPX is a good common codec workflow.

Lee's suggestion of a FG and BG pass is also great advise This way you can strike the best possible key and use that as a "travelling matte" to then key on a duplicate layer that you simply grade for beauty. This beauty layer could even be graded with another platform (Resolve ?) and then comp'd in.

JB

Thank you guys. Curious...what kind of 1st pass would you give it in post to produce a clean key in AE? The flat files are tough to key unless saturation is bumped up....

Thank you guys. Curious...what kind of 1st pass would you give it in post to produce a clean key in AE? The flat files are tough to key unless saturation is bumped up....

The keying pass is all about the transition between the edge of the foreground talent and the green screen.

So you should increase saturation a bit, and you should color balance with your scopes so the green screen is as close to 100% green as you can get it without overtly contaminating the FG talent. It's a balancing act. Be careful about increasing contrast too much, because that can destroy detail used in keying.

Zoom in on your edges, and make sure you're not making your green spill worse with your grading.

When you key it, start by cutting a garbage matte around your talent, so that you need to key out as little of the screen as possible.