Green screen with tungsten = DISASTER

[Fredrik Callinggard]

Now we all know it's not ideal but I'd like to warn you to EVER shoot with tungsten.

I got this article sent to me from a posthouse I worked with on post heavy RED project we did awhile back.

For various reason I had to shoot tungsten on a green screen set on that shoot and believe me... there was no other choice.

We had a lot of troubles afterwards, especially with the blue channel and we guessed the problems was what this article is confirming. So I think it's a good read because it spells it out for you.

NEVER SHOT GREEN/BLUE SCREEN WITH TUNGSTEN WHEN SHOOTING REDCODE!

The blue channel noise is a mayor problem and hopefully something can be done with it. Because I've not only had problems in green screen I've also come across problems a few times where it has been disaster on non green screen shots as well.

It be nice to be able to use tungsten since sometimes you want those warmer hues.

Anyway read the article it's really good and very informative.

http://provideocoalition.com/index.php/aadams/story/red_and_green_screen/

 

[Andrew McCarrick]

That is a problem, seeing as how I prefer to only use Tungsten.

 

[Andrew Martin]

What about CTB gels? Would they help a great deal?

Andrew.

 

[Martin Weiss]

80D filter

 

[Andrew Martin]

Thanks Martin, i'll go pick one of those up - luckily i managed to get 9m of CTB gels (half and full) for free then.

Andrew.

 

[Stephen Williams]

Hi,

Recently I shot a greenscreen on build 16 & Tungsten, no problems whatsoever.

Stephen

 

[Gunleik Groven]

A filter is cool if you compensate with enough light. If not, you end up with a general underexposure.

Also the result is far better, if you develop at 5600k and compensate whiteballance in the matri, instead of using the kelvin parameter and use brightness/contrast instead of iso/exposure to compensate.

Also remember to set DOWN and calculate for a lower ISO under tungsten than under daylight.

THEN you should be fine...

 

[Leo Ticheli]

I've been lighting my Green Screens with green Kino Flo tubes and the foreground subjects with Tungsten. No problems whatsoever.

Build 17, typically RedCode 28.

Good shooting and best regards,

Leo

 

[Mitch Gross]

Actually our clients have found that an 80B or 80C work quite nicely and don't eat up so much exposure.

 

[Hans von Sonntag]

Gunleik is right when he's saying that trying to compensate within RA/RC makes all even worse. Developing at 5.000 K using RedLog is the way to go. You can pull a nice key out of the orange looking GS, providing you exposed enough to the right and at 4KRaw if possible.

There is a simple rule: Never process the footage BEFORE you pull your key, unless you really know hat you do. Thinking that only a by the eyball saturated green looking plate is great for keying is a major missundstanding of this issue.

Nevertheless it's always the best to expose the sensor to it's specs: 5000 K /250 ASA, regardless wether using a 80C or HMI lights.

Hans

 

[Ian Laurie]

I too just shot a green screen test shot with tungsten lighting. didn't even bother lighting the screen properly and it came out great.

 

[Fredrik Callinggard]

Guys the problem is the blue channel.

If you light the set with tungsten, especially the green you will find problems.

The problems occurs mostly at times where the blue channel is needed as in, for example, shadows, reflective material and/or see through material.

It's immediately clear how the compression even redcode 36 is to much. I believe that redcode 225 will take care it of it, but as for now it's not good.

The material we shot looked stunning, but when we did exactly as the article and broke up the channels the blue channel noise in shadows and reflective material became horrible. We ended up with, what generally is 3 plug ins/ nodes in flame., for film. With 18 of them to pull off decent keys.

So all I'm saying if you're doing a post heavy job with a lot of green screen and the objects are not flatly lit or you have reflective material or shadows etc. Go with daylight, especially on the actual green screen.