View Full Version : Lighting for keying


Dan Gutwein
February 10th, 2004, 11:13 AM
I just purchased UltraKey and I am super impressed especially when I consider how bad my lighting is! This leads me to the question --- If I'm standing directly in front of my green-screen (which is 7x5 and haning from a long boom right behind me), the key and fill (softbox) produce good frontal lighting, but a really wicked shadow on the green-screen and this shadow makes it tough to use all of UltraKey's virtual sets, only some work when the shadow is really bad. There is no room above me or behind me to place a "hair light". Should place a 3rd light to the side of the screen and aim it directly at the shadow to neutralize it? Won't that just create an additional shadow on the other side? I only have two 650W Arri's and a softbox. What should I do?

Joe Pitz
February 10th, 2004, 11:27 AM
Dan,

If you can, put some distance between the subject and the green screen. Try a reflector as your fill, which will free up your second light. Take the second lignt and bounce the light off of another reflector on to the green screen. If you use the second light to try to remove the shadow from the key light, you will produce two shadows which will not look natural.

Remember the inverse square law, Make sure that you have more distance on your second light. You do not want to dump too much light on the green screen, just try to remove some of the shadow from the key.

Thanks

Rob Lohman
February 10th, 2004, 11:41 AM
I think the idea is to light it like the shadows don't fall on the
screen at all. One trick might be to use stronger lights on the
screen then on the things in front. More seperation between
the screen and the subjects will help a lot with shadows and
spill suppression.

Jacques Mersereau
February 13th, 2004, 01:14 PM
Large softboxes will help take care of shadows, but lighting for
green and blue screen (for good results) takes a lot of
gear and enough room to make it work.

Dan Gutwein
February 13th, 2004, 03:26 PM
Thank you all for the help - I think my only option for now is to use my Arri 650 to reflect off my big white reflector and reduce the shadow on one side w/o creating another on the other side. Can't do much else since I need the softbox and other Arri to light the subject.

Marc Young
February 13th, 2004, 03:35 PM
If you can afford it, two 4 tube Kino Flo banks could easily light the greenscreen, providing you with a shadow-free background. But the cost exceeds all the lights you have in the foreground.

Mike Rehmus
February 13th, 2004, 06:58 PM
If the greenscreen material is cloth, you can try lighting it from behind. Just hide the hot spot from the light behind the actor. Got to have enough room that the greenscreen (which becomes a light source) light doesn't fall strongly on the subject.

Dennis Sladek
February 14th, 2004, 03:08 AM
Many of us Ultra users have been over this lighting issue, hundreds of times.

Jacques Mersereau
February 14th, 2004, 10:05 AM
The 'lighting for green screen' topic has also been beaten to death here too,
but that said those 'oft asked' questions are usually
answered directly on dvinfo.

*Please excuse the lecture that follows*

Just so you know Dennis,
it is usually not considered good form for someone running
a website to make a blatant attempts at trying to drum up
business from other similar sites (read harshly: steal customers).

I've known Mr. Hurd for a while now and I am well aware of his
'net' ethics. He's built this place from the ground up . . . the right way.

The right way to build a site of your own
is to answer questions on other sites fully and with detail that
establish your credentials. Use your sig to make people aware
of your business/site and hope they go there to tap into your
knowledge base. The other way is if a question goes unanswered,
the answers are incomplete/wrong or if you offer answers that are
extremely long/detailed, *then* you can direct people to your site's recommendations.

I am sorry to report that IMO the tone of your post made it sound as if
this list wasn't "doing the job."

The real 'cut to the quick' answer to Dan's question is:
*You need more gear.*
Any other answer in my view is from someone who hasn't done
green screen work, yet you make it sound as if there's another workable
answer at your site. I find that highly unlikely.

Bottom line: Good green screen=expensive PIA