[Tig] a useful guideline to differentiate between primary and secondary correction controls

Pedro Conforti pedroconforti
Wed Apr 3 10:37:59 BST 2002

Thanks for this detailed guide... these are things we sometimes already
know, but it is great to have this information so clear and short at the
same time. It sure helps to think clearly about the way machines work.

The TIG is going really interesting these days...



Pedro Conforti
Estudios Mega

on 29.03.2002 8:54 AM, NextGen Assoc  Stan Chayka at schayka at nuwaveinc.com

>> From the archives (don't ask), I have dug out this guideline to recognize
> when a control is considered Primaries or Secondaries.
> It is NOT bullet-proof but does point out a very important characteristic
> about Secondaries.
> Primary Controls (i.e. Color Balance, Pre-Store, Film Match, Colour
> Grading) - are used to adjust the overall BALANCE of the image. They allow
> the colorist to establish a balance / ratio between the various pickup
> signals of the color camera / scanner. (i.e. R,G,B and sometimes Y).  The
> purpose of making these adjustments is to establish in the picture, the
> 'correct' color and grayscale content. 'Correct' is not a technical
> condition but rather a desired result within technical limitations. As an
> example, a snow scene is very seldom balanced as neutral white/gray/black
> but artistically a 'cool' or bluish cast is created. But I digress a little.
> Primary correction controls are used to establish where colors ARE and ARE
> NOT in an image by level control of the signals from the pickup devices.
> Level control is typically identified in the U.S. as Gain, Gamma, and
> Pedestal.
> In other countries and languages, these names may differ slightly, but the
> functionality stay equivalent. I don't want those who would ask about
> optical filters or light valves or such to feel slighted. These are all some
> form of Gain control device provided that they can be varied dynamically.
> Otherwise, without adjustability, they are not controls but rather fixed
> compensations.
> Secondaries - are controls used to modify the COLOR content of an image.
> They do not affect the white, gray, or black portions of the image.
> They derive their name from the requirement that they follow the Primaries
> in the image processing scheme. The image having been properly color
> balanced by using the Primary controls, is sent to the secondary processor
> for further manipulation.
> The Saturation, Hue, and Luminance representation of the color parts of the
> image are divided up into useful groupings (i.e. Red, Green, Blue, Cyan,
> Magenta, and Yellow) and controlled independently. Tunable Vector
> controllers are also considered Secondaries as they also perform S,H,L
> changes on images of highly selected color. Many marketing names and designs
> have been used to hype the machines with control over the color content of
> an image. (6 Vector, ChromaComp, KiloVector, Sunburst, and many more)
> Lots of patents as well!
> The key element of a secondary type of control is that it ONLY can change a
> point in an image where color is already present. It CANNOT alter a neutral
> image.
> There is a massive problem with how we as industry members have used and
> abused language terms that can have more than one definition. I have felt
> that this is a normal consequence of marketing trying to create product
> distinction. To communicate technically with each other, we must not
> ambiguous with our words. If a word or term is difficult to 'nail down',
> just mention an example of it in the context of the hardware it could be
> referenced to.
> I have tried to document this explanation in a way as to no offend any
> manufacturer or user and I hope that this help some of you.
> --
> No marketing or advertising on the tig.  Send such submissions
> to tig-announce at tig.alegria.com.
> --
> Thank you John Montgomery for supporting the TIG.

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