The old days of elaborate and expensive Green (or Blue) screening are gone.
Today computers are fast, software is powerful, making the results better
than ever! If you never green screened before you're in for a treat,
it's addictive and you might just get hooked! So many ads from magazine covers
to billboards use this technique and you don't even know it. You see it in the
movies all the time. Now you can add that flare to your photos too.
The screen itself could be a painted board, a bed sheet, a commercial muslin, or
a piece of cardboard from an office supply store. The material itself is
not as important as the uniform color and reflectivity. You do not want a shiny
screen as this spills green (or blue) light on the subject. Size is not important as
long as it's wide and tall enough for the subject. Green is furthest from skin tone,
so it's popular, because blond hair has some green content so blue can be used for
those subjects if desired. The subject may be a person or a product. Almost any color screen can be
used except white and black, and colors in the foreground subject. A test image of only
a picture of the screen can be loaded into Professor Green Screen to test the solid
color range, a value below 25 is great. The lower the value the better the setup.
Screen Lights and Color
Try to use soft, diffused lighting and not hard lighting. You want to avoid
shadows at all cost. Hard lighting casts shadows, soft light is when the
source is hard to detect and the whole area just appears to be lit from
Lighting the green screen uniformly is more important than its actual color.
The color could be bluish, greenish, or have a tint of yellow. That doesn't
matter very much. What is more important is that the background is as close to one
color as possible, and that one color does not appear on your foreground subject.
With bad lighting you will experience a rainbow of colors, making it harder to get
a good KEY. The wider the range the software has to accept the KEY color the narrower the
subject colors can be. This limits your choices of colors in the subject.
You want to light the green screen first,and not too bright, otherwise you will
reflect the green light from the screen. You will want to be aware of the subjects
shadows if they are cast on the screen. Ideally you will want the subject to be
away from the screen to avoid green spill on them. This also helps with depth of field focus.
You will want to light your subject slightly brighter than the screen, the lighter
subject helps remove any slight green spill you cannot avoid. Ideally you should light
your subject with the background image in mind. If the background has
shadows at a certain angle, you will want to light the subject more from that
same angle to 'sell' the believability of the final shot.
The three main benefits of having the subject away from the screen are:
- Minimize green spill on the subject.
- Remove shadows so the color is more uniform.
- Use the focus and (depth of field) DOF to slightly blur the screen.
By blurring the screen you can remove slight imperfections, paint blotches,
ripped cardboard, curtain wrinkles, etc.
Most of all experiment, play and have fun!