On Film: Crawling into a TV - Composite with Green Screen

[Sam David Zhang]

 

For a 35mm short film project. Horror. Very similar to the money shot from Ringu (1998) where the woman crawls out of the television set.

I am designing a shot where a character crawls into the television set, following the general guidelines for the setup described in this YouTube tutorial: The Ring VFX Television

Basically, shoot a plate shot of the television set in the space. Then replace it carefully with a green cutout that the actor can crawl through. Composite in post. Cleanup. Sample images attached below from the tutorial.

 

This all tracks with me, but I have a question concerning exposure and cleanup. Wouldn't an actor crawling through a green cutout cast horrible shadows that affect the key? And since I have to swap out the TV for the green screen cutout, I probably have to keep the room lighting similar in order to make the composite match. Doesn't this mean I won't be properly exposing the green screen cutout? Seems tricky and messy to me. Probably something that can be cleaned up with ease in the digital realm, but the trouble here is that I am shooting on 35mm for school.

Worse still, I haven't had a chance to shoot green screen footage on film. I was planning on 4-perf 5213 200T for a finer grain acquisition for VFX. But I'm not quite sure if there are other tricks in the trade to make the VFX workflow better for something like this.

 

How do I balance properly exposing the green screen with maintaining the moodier tone of the scene? How do I hand off the best quality image in terms of VFX compositing and cleanup?

Thank you all as always.

 

[Robin Phillips]

modern keying tools can handle a lot, but the reality is that this is probably going to require rotoscoping. granted, even that is not a big deal anymore with some of the advanced roto tools out there. even after effects has a rotobrush that can get most of a human figure (or parts if you do the mask in layers) set against even complex backgrounds. 

Action VFX has a bunch of basic tutorials that are really good at getting across the basics, check this one out to get an idea of how some of these roto tools work 

As for the shadow cast, honestly the green screen isnt the concern so much is do you want to have that shadow projected onto the TV plate. Thats a little more advanced, but is a pretty common thing to do. the usual cheat is to take a copy of the mask, make it dark and transparent, then warp it till it looks right on the bg plate. You might also be able to salvage the shadow that spills onto the green screen too, but I wouldnt get my hopes up on that. Regardless these are things even junior artists should be able to accomplish these days. 

One thing to note, make sure your scans are optically pin registered. most scanners can do this now, but you dont want to use like an earlier spirit 4k that doesnt have the feature, otherwise your compositor will be fighting the scanner gate weave. The Scanity (fotokem has one), the regular Scanstation (lots of vendors have this one) are examples of scanners that have optical pin registration. The arriscan has a true physical pin registration and that feature was always the gold standard for film VFX, but a true physical pin registered scan costs a lot because the scanner cant run at full speed.

Back in the day it was always also nice to get an overscan so the compositor would have the perforations to stabilize if need be, but that shouldnt be vital so long as you're using a late era film camera with good registration (others here can speak to movement registrations better than me) and an optically pin registered scanner. Though if you're using like a 1st generation BL, you might want to get an overscan.

 

[Sam David Zhang]

Robin, thank you for all your insight!

 

This is a great resource for me to start digging into. I think I'll loop in my editor to see how heavy a lift the rotoscope job may end up being. I'm assuming that the gate weave in the scan will be a non-issue. AFI hasn't had much problems with the scans Fotokem gave them for 2nd year films.... yet....

 

I just want to reiterate so I know I'm on the right track. It's background plate first, then the rotoscoped/keyed take of the actor crawling through. However, if I want to get fancy, I can also layer in the shadow in its own isolated layer somewhere in between? Would it benefit to "glue" it all together with some very subtle grain layer to make everything feel mixed in? Kind of like a glue compressor in the audio world operating on mixed together dubs/tracks to make it sound like they're unified.