Originally Posted by loadams
My whites "look" white, my dark grays "look" dark gray, it's the 40-70 ire's that have a cyan tint to them.
Wait! Stop right there. You need to figuire out why that could be true, no matter *how* you arrived at that result.
If the mid-tones (40-70 IRE) have a cyan tint, and you're *sure* that the darkest tones (that actually are useful to making up a picture) are really neutral, then the intrinsic response curve (gamma) of the CRT or its drive circuitry for the RED gun does not match the curves of the other guns. The straightforward assumption made during calibration, with instruments or not, is that the curves match. For any one TV, you have no control over them.
(Please be sure first: If you have gotten away from the TV for a few moments to get another beer, say, in an evening-lighted house, the TV *will* look cyan! Your eyes have changed and will have to readjust.)
You can fudge a grayscale nonlinearity it in two ways:
(1) Ignore the almost-black color. You would tweak RCUT to make a realistic b/w picture (Color=OFF) look neutral overall, with whites and mid-tones matching. If you peer into the deepest shadows or display a really dark scene, and things look a little reddish, oh well . . . that is a good compromise because in practice your eye will not see it. If you fanatically adjust the near-blacks for perfection in a dark room, using test patterns, matching your whites perfectly, and then your mid-tones are cynaish or bluish or whatever (been there!), you *will* have screwed-up colors on your picture when you turn the color back up. The eye is very sensitive to mid-tone color! I would accept the compromise near-blacks.
(2) If the midtones are really tinted, you could try fudging one or two of the GAMx controls up one notch. My mid-tones tend a bit yellow when near-black and whites perfectly match. So I first tried knocking GAMB up one point for the GAMM=0 setting (Pro mode). That raised the mid-tone blue, leaving dark and brilliant colors alone. But on my set, it turned out to be a bit of over-correction; I have since made the GAMx settings the same, and I have reconsidered how I judge grayscale linearity, now using *real-world* video sources for judging. *That* has made me happy with the results! Selectively fudging gamma is a legitimate way to cancel out a significant nuisance-nonlinearity in one of the color-drive channels or CRT guns. I hope the need for this is rare.
OTHER COMMENTS: When judging b/w-image color tints by eye, several natural "bugs" get in the way. First, the eye color-fatigues quickly, and staring at the screen must be avoided -- or at least don't fixate. Move your eyes around fairly actively. Second, judging the tint of a bright white is very difficult, especially when the eye has become dim-light adapted. The dazzling white can appear reddish when it is not! One of the advantages of using midday clouds is that they are very bright themselves, and after looking at them, a glance at your screen reveals a color error pretty obviously. It's the back-and-forth that works.
My experience has now been that, when you have clean, decent whites, that's how they look watching your favorite broadcasts and DVDs, too. If the whites look *right,* check that grayscale again by turning off Color. If that looks screwed up, it is! Fix the gray scale to agree with the white. I have found consistently that, given the generous amount of bright-white that makes up many commercials on broadcast TV, especially those 4:3 pillarboxed ones on HD broadcast, you might get the impression fairly quickly that, well, they look a little pink or that they are a little "cold" relative to the rest of the picture. They probably are. So fix *that.*
A very effective method for trying out new white/grayscale settings is to mock them up first using the Warm and/or Cool settings. Remember, these are *offsets* that don't screw up your original Neutral settings. Use 2170P-1/ #14-19 to set offsets you'd like to try, remembering that 31 = no effect.
Example: You're not quite sure you've got white quite right -- looks a little blue to you. So go into service mode, set the user menu to Warm (or Cool, doesn't matter), go to 2170P-1 #14, and set everything from RDOF to BCOF to 31. (That's the same as Neutral.) Now decrease #16/BDOF from 31 to 30, and WRITE. While you're at it, you could also set the other "color temp" preset for a second experiment. Maybe decrease BDOF from 31 to 29 for a larger anti-blue change. Just set the user menu to Cool, and make the same settings as above, but BDOF will be 29. WRITE the result.
Now leave service mode, and go back to watching TV with the menu at Neutral. Still think it's too blue? Try out your new settings by switching to Warm or Cool. Screwed up? Well, your original settings for Neutral are still there, and you can try something else for Warm and Cool.