Primary Color Correction: Color Manipulation Tools - The Art and Technique of Digital Color Correction - page 147

Fig. 4.63
Figure 4.63 shows what the numbers and RGB Parade look like at the
end of the pedestal correction. Now we'll move to the highlight or gain cor-
rection. Once again, we have nice white keys to use as we set our highlights.
The blue channel is closest to being correct and the red channel needs
the most help. Let's set all of these so that the highlights on the white
keys in the middle of the frame are at 100IRE. That might be too bright,
but we'll start with that goal to spread out the tonal range as much as
possible, then we can look at the video monitor and determine whether
100IRE is too bright for this image.
Here's where I left the gain controls ( Figure 4.64 ). There is some green
above 100IRE, but the main shapes across the 100IRE line match across
all three channels. Notice that the blacks in the red channel are slightly
elevated now, because the gain change was so radical. We'll need to fix
that, then decide what we want to do with the gammas.
Now that I'm satisfied that the gains and pedestals match across the
three color channels, we need to decide what to do with the gammas.
First, let's look at the RGB parade display ( Figure 4.65 ) and figure out
what we're looking at. We have only a couple of elements to figure out.
There are the hands, the brown piano wood, and the black and white
keys. What is what in the waveform?
Well, the area between 0IRE and 20IRE to the right of each cell is the
black keys and probably some of the dark wood to the right of the image.
The area in the middle of each cell between 90IRE and 100IRE is the
highlight on the white keys in the middle of the screen. The area to the
left and extending past the middle of each channel between about 80IRE
and 30IRE is the hands. In the red channel, this shape goes up to about
90IRE, probably due to the highlight on the “pinky” side of the hand.