Black Screen Keyer

[Mark Suszko]

You call it a luminance key.

[Zane Barker]

Why do you want to do black screen instead or green screen?

The purpose of green screen is so that you have a color that for the back ground that is not found anywhere else in the image. Using black instead of green or in some cases blue will only cause problems. Why and what problems? Shadows that’s why. Say you have a person in the image that person is going to have shadows on their face. So if you were to key out black then are going to have parts of the persons face missing and it will show your new background on parts of the face.

Hindsight is always 1080p

[John Fishback]

I’ve tried this. Listen to Zane. You don’t want to key on black. It’s big trouble.

John

MacPro 8-core 2.8GHz 8 GB RAM OS 10.5.8 QT7.6.4 Kona 3 Dual Cinema 23 ATI Radeon HD 3870, 24″ TV-Logic Monitor, ATTO ExpressSAS R380 RAID Adapter, PDE enclosure with 8-drive 6TB RAID 5
FCS 3 (FCP 7.0.1, Motion 4.0.1, Comp 3.5.1, DVDSP 4.2.2, Color 1.5.1)

Pro Tools HD w SYNC IO & 192 Digital I/O, Yamaha DM1000, Millennia Media HV-3C, Neumann U87, Schoeps Mk41 mics, Genelec Monitors, PrimaLT ISDN

[Petteri Evilampi]

It works only with light- and bright-colored objects of very simple form and definitely not with a person. It is impossible to put lights so that there is no shadows in her/his face. If she/he for example opens mouth the result will be a hole through the head! And there are eyes with black in the middle and even nose has two dark holes… You should put many tiny little lamps in to the head! (And how do I know this? Because in my youth I was stupid enough to try this with a person, well, not quite a person but a human shaped object known as a politician. I was actually quite happy to make him sweat like a pig in those huge amounts of lighting!!)
Forged it and use green screen.

[Zane Barker]

Even if you could light a person so there were absolutly no shadows the image would look horable. Shadows are what give a image depth.

Hindsight is always 1080p

[Kevin Monahan]

Apply the Luma Key filter. Adjust settings to taste. Best of luck.

Kevin Monahan
60 Blu-ray Templates for Final Cut Studio 2009
http://www.fcpworld.com
Author – Motion Graphics and Effects in Final Cut Pro

[Mark Suszko]

It could maybe work for a difference key. As would white in that case. But I think it would be more work than a good chromakey.

You older guys, have you ever seen some of the VFX shots done for the old “Captain Video” or similar B&W sci-fi serials? They used a kind of luma key in a process camera and darned if it didn’t look pretty good, considering the time it was done.

Back in my junior high days we were still being trained to make titles using white type on black cards and luma-keying it.

…Why yes, I DO have an onion hanging on my belt.. 🙂

[Ken Jones]

Back in my linear days we pulled some fantastic keys from “super black”. In fact, Dave LaRonde spoke about it at length in 2008:

https://forums.creativecow.net/readpost/202/878978

[Jeremy Garchow]

What Mark Suszko says.

It’s very possible (and relatively easy) to create a matte on black. Hope you’re shooting shiny/transparent things, or remaking Tron in 1980 and backlighting :-D. After that you can do a luma matte (key out darker). Or Walter has a great series on travel mattes as they are known in FCP:

https://library.creativecow.net/articles/biscardi_walter/FCPTravelMat1.php

https://library.creativecow.net/articles/biscardi_walter/FCPTravelMat2.php

https://library.creativecow.net/articles/biscardi_walter/FCPTravelMat3.php

Jeremy

[Jay Soriano]

if shooting a video such as, “I’m a Mac/PC” commercial, would a white background be preferred over a greenscreen chromakey?