Introduction to Basic Green Screen Concepts
Green Screen Wizard Introduction Video, see the other videos on the product page.
This document will attempt to explain the
basic concepts of green screen photography. Like many
things, the principle behind the magic is simple, but the details can become
very complicated. We’ll introduce, in this page, the concept of green
screen photography, followed by some examples of use.
The first thing you need to do green screen photography is a green screen. These
screens can be a plastic sheet that costs fifteen dollars, an expensive fabric
screen on a specialized background stand, to a wall painted green in a studio.
In the next chapter, we’ll get into more details about the kinds of equipment
that can be used in green screen photography. For now, consider the image of the
woman standing next to an inexpensive green screen:

In this example we are taking advantage of the outdoor
ambient light to make lighting the screen as inexpensive and simple as
possible. The person to be photographed will stand in front of the green
screen, as shown in this image.

Of course we don’t want the screen to show in our final
photo, so we use our camera to zoom in, or we stand closer to the person being
photographed, so the frame is filled with a green background.

The picture is then loaded on the computer, and Green Screen
Wizard is invoked. 
In green screen photography, we have the foreground image,
which in our case is the picture of the woman. And, we need a background image
that will replace the green portions of the foreground image. So the first
thing we need to do is load our foreground image. So we press "load foreground"
and find the desired foreground image using the open dialogue.

Once we find the image, we load it into Green Screen Wizard
by pressing "ok" and now the foreground image is loaded. At this point the
image looks just like it did in the camera; an image of a women standing
against a green screen.

Now we need to load a background image by pressing "load
background". This brings up another open dialogue and we can select any
background image we like from the professional background images sold by
Elegant Digital, or your own favorite photos. We’ll select a photo of an
aqueduct in Mexico. Pressing "ok" brings the background image into Green Screen
Wizard, and also tells Green Screen Wizard to merge that background with the
foreground.

That’s all there is to it! All the areas of the foreground
photo that were green, are replaced by the background image. We will learn in
later chapters that for the picture to look realistic, the Green Screen
software must deal with subtleties such as thin hair that lets some of the
green through, shadows or wrinkles on the green screen itself. But for now,
simply thinking of all the green areas being replaced by the background image
is the essence of green screen photography.
Let’s try another background. This time we’ll merge trees
with the foreground by pressing "load background" and selecting another
background.

Now we’d like to save our image. Click "save" and Green Screen
Wizard will bring up the save dialogue so you can save the image into the
computer.

So why do we want to do this? Well for one thing, it’s fun.
It allows you a flexibility that was unheard of even a few years ago. You can
put your subject in any background you choose. This gives you tremendous
artistic control over the final image.