aavant is the best and biggest manufacturer of studio photography
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Aavant is the best and biggest manufacturer of
studio/photography
Green Screens and blue screens were the keys to chromakey in the 1970s, the use of blue or green
screens as backgrounds for use with chromakey became widespread amongst local TV news programs,
conjuring up images of cheesy weathermen in garish plaid polyester jackets standing in front of
superimposed maps. The goal of that new technology was to shoot the weatherman in the studio
against a blue or green screen, then delete the background color and insert various images, from maps
to pictures. But very often, the key would be imprecise, causing said weatherman in his garish plaid
polyester jacket to appear to be dematerializing into his map, usually somewhere around the Great
Lakes or Sheboygan. chroma key backdrops
But that was long ago. These days, chromakey and related technologies, such as blue and green screen
effects, have gotten so exact, they're the key to Hollywood blockbusters ranging from the recent trilogy
of Star Wars prequels to such quasi-comic book films as Sky Captain, Sin City and 300. One reason these
effects have taken off in the past few years is that compositing via PC has become incredibly
sophisticated. And that technology has recently trickled down rapidly to the consumer level.
While Hollywood films still have multi-million-dollar budgets, they have saved considerable sums with
green-screen effects, as sets are built in a computer, not by draftsmen and riggers. Similarly, because
compositing via PC is now inexpensive enough that the average serious hobbyist can afford it, green-
screen effects allow one-man video podcasts to have an extremely slick look, even if they're shot in a
garage or a basement. So let's look at some of the elements involved in producing a successful key.
In the past, the main color for chromakeying was blue. Beginning in the late 1970s, there was a slow
industry flip-over to green-colored screens for chroma. That's because of the detail in the green color
channel that digital cameras retain. Additionally, green screens typically require less light to properly
illuminate. However, both of these colors share a similar trait: unless you're videotaping an Andorian or
an Orion, flesh tones don't contain blue or green. So you can remove the screen color without causing
the talent's face to dematerialize.
However, clothes can certainly contain either color. Nowhere was the disparity between costuming and
chromakeying more of a significant factor than in the first Superman movies starring Christopher Reeve.
For obvious reasons, Superman's very blue suit required that special effects technicians film Reeve in
front of one of the first green screen backdrops, rather than the then-common blue screen.
Be sure to advise your on-air talent to dress appropriately, to ensure that his or her clothing doesn't
interfere with the key. This phenomenon is one reason that companies such as Photoflex
(www.photoflex.com) make portable backdrops with both green and blue sides, so that the
videographer can quickly swap out the color when necessary.
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. hand painted backdrops
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.