Posted by nobody special on 11/04/88 11:37

Actually white is ALL colors, blended equally, when you talk about
light. When you talk about absorbtive media like paint and ink, then
all colors mixed in equal proportion come out BLACK.

When using green, the correct anti-spill backlight color is a magenta,
when using blue screen, it's the bastard amber or straw.

Alex, usenet is still the wild west of the net; you come here hat in
hand asking for help, you usually get it, but you also usually get some
snarkiness occasionally, consider it part of the 'fee' you pay for the
free advice, and don't let it get to you, that only magnifies it. If
you come into a group with a boastful-sounding handle like you did, you
can expect people to hold you to a higher tech standard, that's only
natural, and the "chromakeying white" thing was a pretty noobular thing
to say. Like asking the airplane mechanic for a bucket of propwash. If
you're being facetious, it didn't come across like that. Best you let
the jibes go unanswered and they'll die off, meanwhile there is good
information to be had if you ask for it...

Regarding your fringing problem, now we know things are hooked up
right, you have to find whatever controls the unit has and tweak them.
I start with even lighting for the BG that looks to be about 40 IRE
units on my scope: you don't need the green or blue to be super-super
bright, that actually works against you - you want the color
information very saturated, so you can make it a little darker as long
as it is even. The fringing may be coming from reflected green "spill"
shining directly onto your test subject. Move the test subject at least
it's own height, plus about ten percent, away from the background and
you'll have less spill problems and less chance the subject's shadow
will contaminate the background as well. yeah, that means the
background needs to be bigger most of the time, but not as big as you
may think: garbage mates and the like can crop out the studio around a
BG and make it look WAY bigger than it really is.

If you still have fringing, try the magenta gelled backlight now.
Still misbehaving? try slowly adjusting the sampled screen color for
hue, saturation, etc. Look for matte controls called "choke",
"clipping", and the like. Twiddle them a bit more on the fly, see if it
improves anything.

If this is still not working well enough for you on the miniature
test setup, your lighting may be inadequate or the gear may just not be
up to the task of live keyeing DV. Dv is harder to key well than analog
or a better flavor of digital with more than a 4:1;1; color space. But
you may have better luck in post using a plug-in, please try that out
and report back.

And thicken your skin just a little bit, pretend it's the annual family
reunion.:-)

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