Ultra key changing color balance

[Mark Clarkson]

This has been an unanswered question for a few months now. I'm sorry to re-post the issue but I'm really hoping someone will have some useful suggestions for me as this is killing me on a time-sensitive job.

Ultra key is changing the color balance on my footage. Here is one example. The same footage with Ultra Key turned off (left half) and turned on (right half). Any ideas what's going on here and what, if anything, I can do to avoid it?

Here's someone else with the same problem from months ago:

Why Does Ultra Key Keep Changing The Color Of My Video

[R Neil Haugen]

Does your system have the sequence setting set to "Composite in linear color" on? If so, turn it off, and see what happens.

What GPU and GPU settings do you have?

Neil

[Mark Clarkson]

Neil,

Thanks for your response.

Yes, the sequences are set to "Composite in Linear Color." Turning this on and off has no visible effect on the way UltraKey is changing color balance.

GPU Preferences are set to "Mercury Playback Engine (CUDA)." I am running an NVIDIA Quadro K2000.

Mark

[R Neil Haugen]

I wish I had something more ... what other effects are in use?

Neil

[Mark Clarkson]

Only Lumetri, which I've added in after UltraKey to color correct the keyed image.

[R Neil Haugen]

This is ... odd.

Wes Howell​ ... got a weird one here, do you have any ideas?

Neil

[rodneyb56060189]

Just a note on basics...

there are two common key colors … green and blue.  Both are used a LOT and the reason one is used over another is something people tend to spend a lot of time studying. Boardwalk Empire was shot ( the boardwalk exterior ) with BLUE screen. Pan Am was shot with GREEN screen.

Those colors are very specific and only certain companies make the paint and cloth screens with the correct color.

Chroma Key Paint | Rosco

Matthews Studio Equipment 20 x 20' Blue/Green Chromakey Screen 319159 - Filmtools

Now, we know that the screens have to be good screens ( blue or green ).

The next step is to LIGHT the screens evenly and also light your subjects ( talent, etc. )

In order to do that right you need to make a choice.

1) light using 32k tunsten

OR

2) light using 56k ( either tungsten with full CTB, or else HMI )

Google that stuff... for FILM .. NOT STILL PHOTOGRAPHY.

Now, that means you have to choose the correct color temp in your camera ( called White Balance nowadays ).

It must be set specifically to 32K or 56K... IT CANNOT BE SET TO AUTO WHITE BALANCE.

If what you are doing is super critical there are light meters called COLOR TEMP METERS. They measure the color temp of the light and give you correction values for both 32k and 56k ( blue and orange correction) and ALSO give correction for GREEN AND MAGENTA ( in film land that is called plus green and minus green). This green / magenta stuff is extremely typical of fluorescent and sodium vapor sources.

If you have all your ducks in a row as described above, you will have zero problems keying in post.

good luck !

[rodneyb56060189]

Note:

Nowadays there are LED lights made by Arri and others, for motion picture work and they are specifically made to emit 32K or 56K ( and in some higher end models allow for adjustments other than those 2 traditional color temps (ostensibly to 'match' fluorescent or sodium vapor, neon, etc. )  Like if shooting at night at Times Square you may want to match the overwhelming LIGHTS of the environment ( billboards, fluorescent lights in building, stores, etc. etc. )…. but mostly it's 32K or 56K.

[Guest · Accepted solution]

Answered in another topic, but in case thats same issue will repost.

Found solution, don't know about you guys, but what is fixed this for me is:

Effects panel > Ultra key > Spill Suppression > Range

Range value is 50 by default, I'm just put it on 0 and boom no more color problems

[nish_leonhart]

I guess your green screen lighting was not proper.
So the solution is: 
1) Add Ultra Key to the video.
2) Change the setting to Aggressive
(Your video color tone might change now)
3) Go to Matte Generation
4) Go to Tolerance and reduce the Value. 
(This will get back your original video color.)

HAVE FUN