Green Screening a dark scene at DVinfo.net

Go Back   DV Info Net > Special Interest Areas > Techniques for Independent Production

Techniques for Independent Production
The challenges of creating Digital Cinema and other narrative forms.


Reply
 
Thread Tools Search this Thread
Old November 1st, 2006, 09:01 AM   #1
Regular Crew
 
Join Date: Dec 2002
Location: Athens, GA
Posts: 196
Green Screening a dark scene

I've done a lot of greenscreening before but always in well lit environments. I want to greenscreen some shots of someone exploring a cave so it should be relatively dark. My concern is when lighting the greenscreen if I throw a couple lights on it for even lighting I suspect some of that light will be reflected back onto the actor who will have much less light on their face. I am assuming the best way to do this will be to light the green screen with lights hooked up to dimmers then after lighting the talent dim down the green screen lights so that they don't light up his back. But thought I'd run this by everyone in case someone has experience with this.
Dan Measel is offline   Reply With Quote
Old November 1st, 2006, 11:52 AM   #2
Major Player
 
Join Date: Jun 2006
Location: chattanooga, tn
Posts: 721
If you place the talent far enough away from the screen, there shouldn't be any spill. I'd recommend moving the talent out from the screen as far as you possibly can.

If you try to dim the lighting on the screen too much, you'll basically have a darker shade of green, which will not key out anywhere near as well as a bright one would. You want a green screen to be as brightly lit as possible, because the reason green is used in chroma key in the first place is that bright green has a very high luma value, which makes it easier to key out.

Also, keep in mind that you don't necessarily need to use only a small amount of light on the subject as if he or she is in a cave--you can in fact light him or her very brightly if necessary and then reduce gamma in post. If the light source in your cave footage is soft and not directional, you can light the subject very evenly. If there's a directional light source in the cave footage, then light the subject with a hard light with the same general light perpsective.
__________________
-->jarrod whaley.
www.oakstreetfilms.com
Jarrod Whaley is offline   Reply With Quote
Old November 1st, 2006, 02:12 PM   #3
Regular Crew
 
Join Date: Dec 2002
Location: Athens, GA
Posts: 196
Thanks. I was going to shoot the talent about 6 feet from the screen but I can probably move him a little further away. What worried me about lighting him brighter and changing it in post was the fact that he will be carrying a red glowing orb and the brighter lights would diffuse out the red glow. I'll play around a little with this. Thanks again.
Dan Measel is offline   Reply With Quote
Old November 1st, 2006, 02:17 PM   #4
Inner Circle
 
Join Date: May 2006
Location: Camas, WA, USA
Posts: 5,513
Shoot bright, then turn down the contrast/gamma/brightness as needed in post. If you shoot too dark, not only will you get more spill from the brightly lit screen, you will get more noise.

The main thing is to achieve the relative lighting that you want. Are you going for diffuse light, or a hard source with high contrast? The main thing is to keep the faces reasonably well lit. (Assuming that the story doesn't call for them to be hidden in the shadows.)
__________________
Jon Fairhurst
Jon Fairhurst is offline   Reply With Quote
Old November 1st, 2006, 04:27 PM   #5
Major Player
 
Join Date: Nov 2005
Location: Croydon, England
Posts: 277
You could also try one of those light-ring keying systems - do a search under reflecmedia chromaflex - the only problem is finding someone who will hire one out
Paul Jefferies is offline   Reply With Quote
Old November 2nd, 2006, 04:42 AM   #6
Trustee
 
Join Date: Nov 2005
Location: Honolulu, HI
Posts: 1,961
"...he will be carrying a red glowing orb and the brighter lights would diffuse out the red glow."

You could supplement the red glow with a red light just off camera that shines at his face. The audience will mostly be looking at his face, so that is what really needs to show the glow. However method you are using to make the orb glow, you could also try cranking up it's output. There are some super-bright red LED lights out there. Rig it so that most of the light goes back at the actor so the orb itself does not go beyond 100ire and turn white to the camera.
Marcus Marchesseault is offline   Reply With Quote
Old November 2nd, 2006, 12:08 PM   #7
Inner Circle
 
Join Date: May 2006
Location: Camas, WA, USA
Posts: 5,513
One approach would be to use a blue gel on your overall lighting with a red gel on the spot for your lead actor.

Blue cuts out a lot of light and makes faces look colorless. It also gives a feeling of natural or moon light as compared to artificial light.

A red gel lets a lot of light through and will easily swamp a blue gelled light - especially on a face.

The end result will get enough light to the camera to keep it out of the noise, and will still emphasize the red lamp and lead actor. Best of all, it should key nicely over green.
__________________
Jon Fairhurst
Jon Fairhurst is offline   Reply With Quote
Old November 3rd, 2006, 08:25 AM   #8
Regular Crew
 
Join Date: Dec 2002
Location: Athens, GA
Posts: 196
Thanks for the feedback. I'll play around with some of those techniques.
Dan Measel is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > Special Interest Areas > Techniques for Independent Production

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 07:19 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network