Rank: Sony Enthusiant
| Posted: 2005-03-26 18:20|
Here are some basics of global color-calibration settings, independent of any inputs or modes. This sets background black and the drive and cutoff values for the CRT’s 3-color guns. It is basic for color-temperature calibration. My 36XS955 set was *very* far-off!
First, clearing any confusion about the relationship among the three Color-Temp settings, Cool, Normal, and Warm: Normal is the fundamental setting in the service mode, and Cool and Warm are settings that are *offset* from Normal, i.e. Cool and Warm are difference, not absolute, settings. What makes sense to me: Set a “correct” color temperature of 6500K or “White Cloud” (my preference) or anything else for Normal. If it is truly neutral and without any green or pink off-color, then Warm and Cool offsets can be set very closely by adding or subtracting about equal amounts of red and yellow from the Normal setting. (Yellow is minus-blue.)
These are all in group 2170P-1. SBRT = black level, and RDRV, GDRV, and BDRV are red, green, and blue drive (gain) settings. RCUT, GCUT, and BCUT are the equivalent cutoff (black) settings. The six Warm and Cool offsets are set with RDOF thru BCOF, with WBSW as a big warm switch (leave at 0) and SBOF as a brightness offset (leave at 7).
Here is how I proceeded with great results.
NORMAL COLOR. I don’t have a color-temp measuring device; I can’t justify its expense. But Nature provides a nearly-perfect source for comparison: mid-day white clouds illuminated from the front by sunlight (about 6000K), seen thru an open window or screen, NOT glass. You can twiddle more precisely later, but this is free from green or magenta contamination. Beware of foggy overcast (too cool-blue) or rainy-moist overcast (yellowish). Just the right overcast may do the trick, but you won’t really know how cold/warm it is.
Do this in black-and-white: Set the Color slider all the way down to minimum with your remote. You are going for a *perfect* B/W picture. Set Color Temp to “Normal.” Make your room fairly dim — no artificial light! No green light reflecting from trees. Make sure you’re in Pro mode and stay there.
In each case, **write down the original settings** just for safe-keeping. Log what you’re doing!
Set your Brightness and Picture sliders with the remote to 31 (mid-scale). Use Digital Video Essentials or Avia DVD, and use a video-PLUGE pattern or “video black” on the disk as a decent black standard. Change the code 2170P-1 #5-SBRT to set video-black as the barest screen glow. For PLUGE, follow the DVD’s instructions. Black level for off-air/cable broadcasts are generally complete anarchy, but your local HDTV station or two may broadcast good black. This is only a starting point, but it’s okay for now. Save the settings.
Go to code-group 2170P-1. Leave red settings alone. Look out the window at those clouds. Look back at the TV, and set #7-GDRV (green) and #8-BDRV (blue) until the whites are *white* to your eyes. Go between the outdoor view and the TV (big brightness difference, unfortunately) until you get it right. Cycle among your TV channels for different material to verify you’re getting it right. Unless you have a color-perception problem, your eyes don’t lie: if it looks white, it is white. The clouds “calibrate” your eyes for a short time.
Now sit in front of the TV, and adjust #10-GCUT (green) and #11-BCUT (blue) until the darkest areas *match* the color of those whites. There is some interaction here, so twiddle until you think you’ve got it: a really good B/W picture with very few off-color areas. Note that too-bright white areas may develop pinkish or greenish casts from heating of the CRTs aperture-grille wires — a drawback to the big tubes. Lower the Picture setting if that’s the case. You should be able to get a B/W display that maintains consistent color from shadows thru highlights.
Make some further refinements while those clouds are still there! The GCUT and BCUT adjustments may have modified the accurate white. Go back and forth a couple of times. Save the settings.
THE OTHER COLOR SETTINGS are determined by the codes #12-WBSW through #19-BCOF. WBSW=1 adds a huge, unknown warm bias to the color, so I don’t use it. Leave WBSW set to 0. The offsets are zero (no effect) when the codes are set to 31. Leave SBOF at its original setting.
Change the Color Temp menu-setting with the remote to Warm. Set RDOF to 33, GDOF to 31, and BDOF to 29. Set RCOF to 33, GDOF to 31, and BCOF to 29. Save the settings.
Now change Color Temp to Cool. Set RDOF to 29, GDOF to 31, and BDOF to 33. Change RCOF to 29, GCOF to 31, and BCOF to 33. Save the settings.
These offsets approximate a mild change in color temperature for Warm and Cool, not the useless super-warm and bluish settings my set came with. Sheesh! But use larger offsets if you wish. You can re-do all of this another day, as your wisdom increases, but this should be a huge improvement on the factory settings.