I am going to shoot a project that is going to be all bluescreen/greenscreen.
I have some Ideas on how I would like to do this but want to get some
I am shooting HiDef and was wondering if the camera prefers Blue or Green
screen and if the screen should be under key in the exposure or over key,
assuming the key is not at a low t stop.
Any feedback is welcome.
Ed wrote :
>I am shooting HiDef and was
wondering if the camera prefers Blue or >Green screen…
There are many variables with blue or green screen that need to be considered.
They all need testing beforehand, as you know there is limited time while
you are shooting.
* What is the compositing
program you are using? (Ultimatte or Primatte, etc.) Some
software do a little better than others with fine detail and
general key pulls.
* What color of hair
are on your key actors scalp? Blond actors on an slightly
over-exposed green screen is harder to rescue than blue screen,
especially with camera movement and action scenes.
Don't blow out the highlights with hair and try to keep the whole head
in focus, if possible to avoid digital haircuts. An underexposed blue
screen reveals its true noise at the bottom of the prism, and at -3db
gain in a controlled environment, it can turn ugly stretched out noise
into a normal looking "grain".
* Detail and color
matrix set ups on your camera can be your compositors worst
enemy. A camera matrix that looks good on a normal set can
give you a false sense of evenness on the screen set monitor.
One can always garbage matte the outside slop. Color correct
later with more control and quality to reclaim what you are
missing by shooting in a more raw set up. It is the edge quality
for the key that is important, any edge detail can cause a
bad effect, keep it smooth.
* Do you have a controlled
environment or location work? Your at an extreme disadvantage
without a waveform monitor on set. An uneven screen with variable
densities will add time to the composite. Tight spaces create
wraparound spill and tinted lens flare, flag off what you
don't need. Green is easier to light in an exterior setting
with even indirect daylight. Blue seems nicer in a moodier
lighting setup and just to work around with your eyes.
* Screen exposure should
really never be over key, unless there is no key, as in a
dim moment or silhouette shot. Actually, once you have lit
for the screen, you have your T-stop, (+/-), then your key
light is built around that exposure setup. Lock it into your
It is helpful when the clock is ticking past at hour ten. Think about
your depth of field beforehand and what you will need focus wise to base
your screen T-stop at. Have the director rehearse some potential blocking
in a like space and you use a tape measure to make notes ahead of time.
And if you want to use a polarising filter for the floor or highlight
reduction, there goes some more T-stop.
Blue/Green screen lighting is not a dim subject, unless you never see
the actors feet it seems.
Let me know - Good Luck,
Director of Photography
Los Angeles, CA