Can I achieve effective keying if I use green lights to illuminate a white wall?

Question

I do frequent video shoots of a speaker standing in front of a white wall at the end of a hallway in a corporate office with limited clean background availability and tight spaces. I don't usually have the ability to carry a lot of extra gear with me, so setting up complex backgrounds and lighting is not easy. The existing lighting is pretty standard corporate ceiling fare, some fluorescent (possibly updated to LED) and some other locations with newer LED recessed lights. We've been mostly successful in keying with the white, but it's difficult due to the white wall and its orange-peel texture.

I was thinking it would be nice to be able to set up a green LED or two to wash the wall in green, and then buy some portable and lower cost white LED panels to place in front of the speaker, who could step away from the wall a bit to avoid green spill.

Does this sound like a good idea?

Answer 1

My favorite quick, cheap, DIY greenscreen over the years is a gallon of chromakey paint and a sheet of drywall from Lowe’s or Home Depot. One sheet is enough for a seated, talking head, like you see in most corporate interviews, and the rigidity of the drywall keeps it flatter and more even than any fabric solution. If you can get away with storing a sheet of drywall somewhere on site, this is a good option.

Answer 2

I think if you light the wall green, you will get lots of bounced light back onto your subject which will play havoc with your key. Amazon does very cheap greenscreens now, which work pretty well so long as you have a way to evenly light them and your subject is isolated far enough away from the screen and lit separately.

Answer 3

I interned at a company many years ago which used a retro-reflective background coupled with a green LED ring light, which surrounded the lens. The wall looked silver/white when the device wasn’t in use, so it blended into their office better than a chroma green wall would.

When the device was in use, it’s trick was that it DID cast green spill onto the subject, but because it was a ring light aligned with the lens position, the spill contribution to the talent was relatively even and flat, but the retro-reflective material shot a highly chromatic green straight back to the lens. White balancing at the center of the frame would be enough to counter most of the spill, and the contrast provided by the reflective material was enough to pull a decent key.

This was long enough ago that I’m fairly certain they weren’t shooting a format any better than 4:2:2 8bit, and it might have even been 4:2:0 or 4:1:1.

I don’t know how much effort went into correcting green falloff from the center of the frame outwards, but the company did also introduce me to the software ScopeBox, so they probably did tune it somewhat.

I don’t know the exact brand they used, but a ddg search for “chroma key retroreflective ringlight” was enough to return relevant results.