The Keys To Chromakey:
How To Use A Green Screen (page 2)

In the past, a television production required a dedicated studio and lots of expensive, cumbersome overhead lighting to make the scene appear evenly lit. These days, with a couple of grand for a lighting kit and a digital backing, it's possible to "build" a virtual set that looks like it costs a lot more than it actually does. Digital Juice (www.digitaljuice.com) is one of several companies that sell slick-looking video backing tracks which you can loop to form a digital background, so you can green-screen the talent in front of it. Combining these clips with a DV camera, a tripod, lights and compositing software makes it possible to turn virtually any garage or basement into a video studio.

What's the future for do-it-yourself green screening? Serious Magic (www.seriousmagic.com), which became a division of Adobe recently, points the way towards one scenario. Its Ultra 2 program (now available bundled as part of Adobe's new Creative Suite 3 Production Premium kit) combines a fairly big collection of incredibly slick-looking virtual sets along with their compositing program.

The end result is that you can position the talent in front of a small green screen, record via a standard Mini DV camcorder on a stationary tripod and proceed to composite in all sorts of virtual sets, along with some amazingly slick camera moves created inside the compositing program. These include helicopter shots zooming into science fiction backgrounds that Gene Roddenberry would have given his eyeteeth for during the heyday of Star Trek. What was science fiction a few decades ago is now science reality.

Of course, these virtual sets aren't for everyone: they may be too overwhelming or "arch" for a production that will ultimately end up as a five-minute clip on YouTube. A less complex backing may be more appropriate for some productions; obviously, experimentation is the key.

As a case study in how green screen and chroma can make a small operation look network-slick, it's worth studying the production techniques employed by Bryan Preston. He's the producer of the five- to ten-minute daily video clips for Hot Air's (www.hotair.com) daily Vent vidcasts. Preston extensively uses chroma to generate digital backdrops behind the on-air talent, such as Fox News panelist Michelle Malkin. Preston recently told me, "We don't have a studio per se, so we're using a Lowel Tota-Light kit. Basically, the way I set things up is that I light my talent with four lights. I point two Rifas - a large Rifa and a smaller Rifa - at the talent. And then I have two Lowel Pros, little 500-watters, as my rim lights. I light the green screen itself with two umbrella lights, Lowel V-Lights."

Preston says that the nature of green screen requires lighting it separately from the talent. "The trick, of course, with any green screen, is to get enough light on the green screen so that the green hits the right tones" for keying, he adds. "But you also don't want to get so much that it bounces onto the talent. So I've played with distances to get Michelle far enough away from the screen, but close enough to it, because the green screen itself is a five-by-eight foot portable green screen." To cut down on spill, Preston eventually ended up placing his talent about six feet from his Botero collapsible fabric green screen.

This article only scratches the surface of what chromakey and green screen can do. You might not create the next Sin City or Star Wars, but to elevate the quality of your next YouTube clip, green screen can go far towards creating champagne-quality video on a Budweiser budget.

Ed Driscoll is a freelance journalist covering home theater and the media.

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