[Tig] Color Grading in NLEs

Sam Holtz SHOLTZ
Thu May 8 06:11:33 BST 2003


Craig you are confusing the issue. the primary colors in light (not in print
paper) are always have been (R)Red (B)Blue and (G)Green  The term Y is
utilize to represent Luminance (it is preferable to use the letter
(L)Luminance  witch is the sum of R+B+G  approximately.  Red is about 22%,
Blue is about 11% and Green is about 67% (this is not exact amounts, just a
rough idea to explain the concept. Therefore you can not say that Y is one
of the primary colors.  The secondary colors are the Vectorial addition of
two of the colors  the secondary colors. for example Yellow is the Vectorial
sum of Green plus Red, and vectorialy represents is 180 degrees form Blue,
therefore you can say that Yellow is minus Blue from Luminance. Cyan is the
Vectorial sum of Blue and Green and vectorialy represents is 180 degrees
form Red , therefore you can say that Cyan is minus Red from Luminance.
Magenta is the Vectorial sum of Red and Blue, therefore you can say that
Magenta is minus Green from Luminance. To my knowledge There is no tertiary
Colors, and that may be a way that someone made up to represent setup,gamma,
gain from secondary, similar the three sets available to the primary's.  In
other instance, in order to avoid patents, someone decided to artificially
create instead of 6 vectors, 3 primary's 120 degrees apart, and 3 secondary
also 120 degrees apart, but rotated 60 degrees from the primary's (as a
function of the Vectorial addition) they created 10 vectors  36 degrees
apart and / or  12 vectors 10 degrees apart. This do not exist as primary's
or secondary. Maybe they baptize them terciary's This additional
complication has no other purpose but to avoid the original Patent by
Monahan (RCA), an later used by CBS and Philips Called variable matrix. And
re-patented the application by Armand B. Sarabia, et al. when manufacturing
Corporate Communications Color Corrector. The Patent was sold to Rank
Cintel, and since Rank Cintel as a company does not exist, I am unaware if
Cintel a new organization that purchased the assets from Rank Cintel if they
purchased that or not. Never the less I do not believe the patent is
enforceable with the present technology. All the concept of windowing is in
order to change the color settings within a portion of the frame. The
windowing technology has evolved from a simple rectangle to a traveling
mate. this was to change flesh tones or wardrobe that was the same color
value of another item or subject in the frame.

Sam Holtz - CEO / President
email: samh at ieee.org and sam at digitalinertia.com
Digital Inertia, Incorporated
URL: www.digitalinertia.com
19174 Doral Place / Porter Ranch, CA 91326-1223
818-366-3659 / FAX 801-912-3983 / CELL 213-305-5960
Statistics are like bikinis.  What they reveal is suggestive, but what they
conceal is vital
----- Original Message -----
From: "Craig Leffel" <craig at opt1mus.com>
To: "Kevin Monahan" <videoweb at pacbell.net>
Cc: "The New TIG" <tig at tig.colorist.org>
Sent: Wednesday, May 07, 2003 4:49 PM
Subject: Re: [Tig] Color Grading in NLEs


> Don Trepczyk supports the tig.
>
>  Kevin wrote:
>
>
> > How do you choose your color combinations? I asked a number of
> > colorists I know and they have not heard of using color theory to assist
> > in color choice. I assume that once you get to be a pro colorist, this
> > is more intuitive-I can understand that. But am I on to something with
> > this idea?
>
>
> I would say you need to re-think your approach. Coming up with a color
> balance that "works" will always be dependent on the material you are
> starting with. You need to break your thinking into; Primary, Secondary,
and
> Terciary reasoning. I don't mean secondaries in the classic color
correction
> model either. I mean RBY are primaries, and their combinations are
> secondaries.  Combinations of 2 secondaries, or a secondary and a primary
> produce a terciary. In video, as well as photographic printing, all colors
> can be derived from 3 basic primaries. The only difference is Green
becomes
> a source for luminance as well as a primary. It's STILL a blend of Blue
and
> Yellow ( original real world primaries ).Relationships of the original
> primaries in a finished grade are based purely on the source material and
> what the desired outcome is. I have been involved in a number of
dicussions
> about this subject for workstation color enhancement programs. There is NO
> "preset" my friend. It takes work, experience and an education either from
> an institution or the school of hard knocks. Do not expect that you will
be
> able to come up with "preset" pallettes of color combinations and have it
> make any sense to anyone operating the box. We are in the middle of doing
a
> number of webisodes / commercials / DRTV work for the United States Army.
We
> are "color correcting" much of it in an Avid DS. The editors would like to
> know how they can save what we do. It's really a problem for Avid and the
> color correction impaired programmers they have working for them ( or FCP
> for that matter ), but the idea is that there should be a way that you can
> save color corrections that you build in a seperate list, with a picture
> attached. Just in case anyone is listening, 2 pictures would be better.
One
> of the image before color correction, the other AFTER. Then the editor (
or
> better - Colorist ) might have a slight clue about how the color
correction
> is going to affect the image they are working on. Simply naming them and
> saving a file is not going to cut it. Try and come up with a good name for
a
> correction that adds 50% contrast, removes all blue, adds 25% saturation,
> leans green about 10% more than Red, has a matte channel that acts like a
> power window for a vignette, has a luminance curve manipulation, and has a
> gamma push. EVEN IF you could name it something that fits, the only way
> anyone could use a name only system is by defining a large list and
playing
> the double click game down the entire list until one works. That does not
> sound efficient to me at all. I have a better idea, just like I tell our
> editors, when you need to color correct something, call the colorists and
> one of us will come down and sit in your chair for a few minutes...
>
> BTW, you can tell the folks at FCP to throw away the curve base portion of
> their color corrector. Why all the yokels out there building these things
> think a curve based part of the corrector is vital is beyond me. I realize
> many graphic artists use this kind of system everyday. Up until now they
> haven't had any better tools. "Color correcting" by moving points on a
curve
> and waiting to see what happens is like drinking beer out of a baby's
> bottle -- it's the wrong tool for the job. Curve based color correction is
> for specific tasks -- not for making images. While your at it, throw out
> Histograms too. They're just as worthless.
>
>
> Hope it all helps Kevin --
>
> Yours in Knobtwisting,
>
> Craig Leffel
> Senior Colorist
> Optimus
> Chicago
>
>
>
> --
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