[Tig] Naming color shifts

[Richard Kirk]

Hi.

Here is an allied subject to the naming-of-colors thread...

When adjusting the white point, I have L*a*b* conbtrols. The a* control 
goes from green to pink (roughly), and the b* control goes from blue to 
yellow. These are pretty much the Heering primaries. I notice the 
following...

If you are trying to remove a small cast, it is easy to distinguish 
yellow from red or pink but it is harder to distinguish green from blue. 
I almost seem to need a third control to go from green to blue. When 
setting the white point, this may be complicated by contributions from 
the peripheral vision.

Some people find it easier to state the color cast they see (pink, 
yellow) rather the correction (more green, more blue). Clearly, if you 
have two images, then making a spot decision ought to be symmetric -  if 
one image has a 'yellow' cast, then the other  will have a 'blue' case 
with respect to some 'average'. However, if one image is constant, and 
the other is changing because you are doing a sequence of changes, it is 
easier to state the color you see than trying to invert it mentally.

Some people have difficulty using the terms 'magenta' and 'cyan'. They 
may think of them as 'minus-green' and 'minus-red', and the mental 
inversions are getting in the way of their perception. Pink works 
instead of 'magenta' - it is ambiguous, as people refer to 'flesh pink' 
instead of 'panther pink', but this does not seem to get in the way. I 
suppose 'aqua' might work instead of 'cyan': I don't know why but 'aqua' 
and 'teal' are not words that come to mind for me. Maybe, what we were 
actually wanting in the last thread was a set of good terms for color 
differences. What is the Crayola 'cyan', anyone?

Cheers.
Richard Kirk

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