View Full Version : The True Power of Green Screen!


Kevin Lewis
September 13th, 2010, 08:35 PM
This may be old news to some but I just ran across this on you tube and thought it was great!

YouTube - Stargate Studios Virtual Backlot Reel 2009 (http://www.youtube.com/watch?v=clnozSXyF4k)

Jonathan Jones
September 13th, 2010, 10:43 PM
I'd seen some of those clips before, but not most of them. Thanks for the link. That is some pretty amazing work. And considering the bulk of it is in weekly series programming where turnaround is fairly speedy, the results of their efforts are still very convincing.

-Jon

Dean Sensui
September 13th, 2010, 10:51 PM
I read about this in Studio Daily last year. Inspirational, ain't it?!

Terry Lee
September 17th, 2010, 03:05 AM
simply amazing...I love greenscreening...

Its alloooot of work to get it right..but the pay off is worth it.

Simon Denny
September 17th, 2010, 05:26 AM
Man I wish my keys came out looking as good. What software do you think they use?

Cheers

Dan Brockett
September 17th, 2010, 08:22 AM
I interviewed the principals of Stargate earlier this year for the final season of 24. Amazing work and what is really interesting is that they shoot all of the BG plates and footage on a suitcase full of 5D MKIIs that they drag to NYC. That is exactly how they shot the 24 episode that has scenes shot at the UN. Very convincing technique they use, very innovative and relatively low cost in comparison to hiring crews in NY and doing big location shoots.

This kind of stuff is the future of filmmaking, I truly think traditional location shoots with large union crews will eventually be replaced by green screen shoots indoors and out combined with virtual BGs and environments. Hollywood will always go for cheaper, if the results hold up and based upon Stargate's work, I think it can. Right now, it is a high end specialty, but eventually it will become much cheaper and easier to do the compositing convincingly.

Dan

Terry Lee
September 18th, 2010, 12:53 PM
Its almost ashame that new technology is replacing these old traditions.. Ten years from now film schools wont even teach what seamed like the necessities of film and set design.

Paul Cascio
September 18th, 2010, 02:19 PM
I was surprised by how imperfect the the green backgrounds were. In many cases there were significant seams and uneven lighting. Anyone know what software they use?

Dean Sensui
September 18th, 2010, 05:47 PM
Here's an article that mentions something about what they used in Helen of Troy:

helen of troy and usa network and stargate digital and helen of troy and special effects and maya and softimage and after effects and special effects and stargate digital (http://digitalcontentproducer.com/cg/video_virtual_helen/)

"We simultaneously started building new 3D elements [mainly in Maya and Softimage, later using After Effects for compositing, in conjunction with 2d3 Boujou motion tracking software]. "

Set design and cinematography skills still apply. The difference is that there are no tangible set pieces. The tough part is for the actors: fewer surrounding cues to provide a performance reference.

Everyone's probably seen this already, but this was with After Effects and Primatte:
Green screen opening shot for HGF-205 (http://hawaiigoesfishing.com/greenscreen_demo.html)

In this article, On the Virtual Backlot (http://digitalcontentproducer.com/dcc/revfeat/video_virtual_backlot/), Sam Nicholson of Stargate said, "The issue of what makes daylight look like daylight is a complicated one, but when you composite in the actor, you can tell instantly if you got it right or not. "

That applies to the simple shot I did above. It's not just matching the direction and quality of light. It's also a matter of matching what CG artists would call ambient light, or the color of light that fills in the shadows. In any situation, shadows are seldom neutral. They're always tinted by reflections from the sky, surrounding objects, etc.

These digital tools can serve a useful purpose. In our case it saves us from getting our host up at 5 am to catch the sun at 7 am, while risking bad weather, noise and other unknowns when shooting on location. It also allows us to use locations that could be hundreds of miles away, or hard to access, and still employ a teleprompter.

Simon Denny
September 18th, 2010, 09:15 PM
Hi Dean,

Nice key in the fishing seg. I noticed the talents shadow in the key and not on green screen, how did you achieve that?

Cheers

Dean Sensui
September 18th, 2010, 10:05 PM
Hi Simon...

The shadow is a duplicate of Cindy's keyed image. It's darkened until it's completely black. Opacity is set to some low level, perhaps 30%. The keyed image is then distorted to the right proportion and position, and softened as needed.

Simon Denny
September 18th, 2010, 10:26 PM
Thanks Dean,

I thought you may have done something like that.

Cheers

Kevin Lewis
September 18th, 2010, 10:35 PM
Dean:
what type of lighting did you use to light the green screen? Whats your thoughts on using flourecent lighting for the screen?

Dean Sensui
September 18th, 2010, 11:03 PM
Kevin...

There are two Lowel Tota lights on the green screen. They're set up the same way you would if you're doing document copy work. Each light is about 45 degrees off to one side to provide even lighting.

There's just one DP light on the talent, placed in a position to match the background lighting. For daylight simulation, the higher and/or farther you can place the light the better. Less falloff over a larger area.

Bruce Phung
September 19th, 2010, 09:33 AM
Dean
Can you please link a site where you bought the large green screen? I normally see the small one only.

Dean Sensui
September 19th, 2010, 12:32 PM
Bruce...

Check out EEFX.com. The one I got is 10x20 feet. There's a seam down the middle but it doesn't show up in the key at all.

Storing it is simple as it can be folded up or rolled. Wrinkles come out readily. It lights evenly.

Bruce Phung
September 19th, 2010, 01:07 PM
Thanks Dean. I'll go check them out.

Kevin Lewis
September 19th, 2010, 03:28 PM
Dean, as far as the green screen is concerned, are you using a soft box or umbrella with the tota lights?

Dean Sensui
September 19th, 2010, 03:38 PM
Kevin... I just use the lights on the green screen straight. No filtration, diffusion or bounce.

Kevin Lewis
November 2nd, 2010, 05:42 PM
Dean:

Do you think there is a big difference in the quality of the key when using the foam materiel like you have as oposed to a 100% Cotton fabric?

Dean Sensui
November 2nd, 2010, 11:39 PM
Kevin... The EEFX.com screen flattens out nicely. Cotton retains wrinkles.

Anything that makes the green screen more consistent allows better control in the keying process. Especially if you're interested in being able to key stray hair, veils, translucent items, etc.

So in short, yes. It makes a difference.

Kevin Lewis
November 12th, 2010, 07:08 PM
Dean:

I know yu used totas for the green screen, but what did you use tolightthe subject. A:so, what frame rate did you shoot at?

Dean Sensui
November 12th, 2010, 10:19 PM
Kevin... To simulate hard sunlight I often use a single DP light. A Tota light works for that, too.

Frame rate is 1080p30.

When lighting, take into consideration the color of the light filling the shadows. It might not seem like anything to even consider, but in real life shadows are seldom neutral. They're always tinted by ambient reflective materials, whether it be the sky, trees or nearby structures.

Kevin Lewis
November 13th, 2010, 11:14 AM
Dean,
thanks for the info. I have a shoot coming up which I will use green screen for. I have a tota light kit and wanted to getyour thoughts on lighting the sudject with a softbox attached to the tota as oposed to some other type of diffusion. It seems that alot of people use the softbox when lighting the subject for a green screen shoot. I am thinking about purchasing a softbox but wanted to get as much info on it first. Thanks.

Dean Sensui
November 13th, 2010, 02:20 PM
Kevin... The light illuminating your talent has to match the light illuminating your background. If it's late evening in your background plate and you light up your talent with a softbox portrait-style, it's going to look all wrong.