sotti
03-27-08, 01:43 PM
Okay so I think I have my display very close to being as accurate as I can make it. The 42rv530 that I have forces you to make quite a few tradeoffs to get anything resembling an accurate calibration. That's not to say the picture looks bad, just that you'll have to weight different aspects of images and decide what looks best to you.
I used a spyder II, so my results may be a little less accurate but the principles of my calibration should be sound.
Before reading this post you should read this post http://www.avsforum.com/avs-vb/showthread.php?t=852536. It covers the high level concepts in far more detail than I am about to. I’m also going to be light on specific details (xyY, CDM values) and attach several calibration files at the end.
The big issues with my set and I believe many are applicable to at least similar generation Toshibas and previous generation Toshibas if not all LCDs.
1) The gamma starts falling off aft 50%, With the darkest static gamma setting (-5) my set runs about 2.1 gamma, but above 50% the gamma drops (screen becomes brighter, washed out) above that, ending at ~1.7-1.8 gamma at 90% white.
2) The Green primary is misallocated v STMP-E or rec.709 color gamut. It is naturally about dE of 20 away from the rec.709 primary location.
3) Blue simply does not want to track with red and green.
Before we can address these issue we need a better understanding of what controls are available to us via the user and service menus.
User menu:
contrast This essentially is a component of where the signal gets clipped at the high end. Raising it causes the image data to get clipped at a lower value, lowering it preserves image detail. (It also shift the gamma tracking, I'll get into that later).
backlight Kind of a no brainer, this decides how much light should be emitted into the screen, raising it raises and lowers both black level and white level. IMHO the lower you can run your backlight the better off you'll be.
brightness Brightness effects primarily the black level of set, raise it high enough and you can see BTB data being passed. It does increase the brightness somewhat across the whole range of colors.
color The color control is a pretty straightforward color control, it changes the luminance(Y value in xyY) of your colors with minimal effect to grayscale.
tint The tint control also works very well, it changes the hue of the secondaries rotating them on the CIE triangle with very minimal effect to grayscale or primary values.
ADV -- static gamma This control is mapped backwards from the way you'd assume it works based on numerical gamma. -5 is higher gamma number, +5 is a lower gamma number. (-5 yields highest gamma setting).
ADV -- color temp The values are simply offsets for your RGB drive/cuts (get into those in a minute). This means regardless of what you set it to here once you do grey scale the end results are the same. If you calibrate cool to D65, the calibrated cool will exactly match a calibration where you decided to use warm when you calibrated white to D65. I decided that since every setting yields the same result (for that calibrated setting) I would calibrate normal to D65, so if I wanted I could have a cool and warm setting that will shift the color temp up or down (anime, b&w).
ADV -- G & B drives I don't actually recall if they are labeled drives. These two colors are available in the user menu by pressing enter on the color temp then selecting down. These controls map directly to Green and blue drives in the service menu and have the exact effect those controls have. I believe there is no red, because red is the color that clips first in all sane color temperatures, so since it makes more sense to leave it steady and move the other two colors next to it.
Colormaster My set on has "colormaster" and not the pro version which is on the cinema series displays. I have found that these controls actually work very well, the trick is to use the brightness setting as little as possible. +-5 for brightness is fine, in the 5-10 range you'll notice a small amount of macro blocking. I do not recommend setting any brightness over 10 in color master. Hue does what you would think rotating the point around the CIE diagram. Saturation, does do some saturation moving the color closer or further from white, but it also has a profound effect on the colors luminance and I found could be used as sort of a course gain for color luminance.
service menu
Click mute, mute on the remote, hold down mute the second time and press menu on the TV and you're in. (unless otherwise noted 00 is the lowest setting in the service menu and FF is the highest, this is hexadecimal and give you 256 increments).
RGB drives These effect your grayscale on the high end. If you turn them up to high you will begin to blow out the TV’s menu system. These values in combination with the contrast setting determine how much light the TV will actually pass through. I have found no value in trying to run these values higher or lower for calibrating gamma or color. The TV image will be very similar with these values >90 and <70 but above 90 the user menus begin to blow out. These controls are generally fairly sensitive not needing more than 2 or 3 clicks to change a few percentages. These controls interact with brightness, contrast, and RGB cuts.
RGB cuts These effect both the white balance for the low end of your grey scale, but also your black level. These are also unique in that 80 is low and 7F is high, so a setting of 80,80,80 provides the best black point (darkest) while a setting of 7F,7F,7F provides the worst black point (brightest). Blue, our habitual offender, is far and away the brightest color in the low IRE patterns, so leave blue at 80 and balance the Red and Green cut off blue. I found depending on how your calibration is going you may want to sacrifice some grayscale balance in the lower IRE for a better black level. These controls are not very sensitive and will sometimes need to move as many as 20 clicks to move 3-4% when balancing a 30 IRE test pattern. These controls interact with brightness and RGB drives, and to a lesser extent contrast (but not by much).
BRTC, COLC, UVTT I’m ganging these three together because they are very similar. BRTC is brightness center, COLC is color center and UVTT is essentially tint center. These service level controls are essentially moving brightness, color and tint for you across all inputs. Since brightness, color and tint in the user menu are per input, I believe it makes more sense to these values corrected here in the service menu so you do not have to duplicate the most accurate setting across all inputs that you use.
CONTX CONTX is contrast max slides where the top end of the user contrast scale is on the range of contrasts available. It has the exact same effect as setting contrast in the user menu. So if you select contrast of 50 in the user menu and raise the CONTX up enough eventually, even at a user contrast setting of 50 you will start clipping WTW and eventually white below peak white. I set max contrast so that a 100 IRE pattern for video white is just below clipping with white calibrated to D65. I did this since you couldn’t possible make an argument for having the contrast clip into any of the lower IRE patterns and lowering user menu contrast can raise the clipping point to 255 and above easily (and as you’ll see in the next section I had to go way beyond that).
So these are the controls that we can use to tune the display. Now that I have explained what I have found to be the functionality of the display here is what we can do to try and correct the biggest out of the box offenders.
The gamma problem
This is far and away the one of the biggest compromises you’ll have to make. I decided that after setting up contrast so 235,235,235 @ D65 is just barely below clipping with 100 user menu contrast, I lowered user menu contrast all the way down to 50. Because contrast is so low, I also turned my backlight up a bit to 55. What this does is essentially move white down to about where 70% would be on the gamma/rgb levels/grayscale. This allowed me to have an average gamma of just over 2.1 and I was able to get my 90% gamma up to 1.95, much better than where I originally started. But you definitely trade off some dynamic range to get this.
The green problem
Colormaster can only do so much. I moved green to -30 saturation and that seemed to get green as close as possible to rec.709 green. After that you pretty much have to give up on the rec.709 color gamut and calibrate your display to its unique color gamut, the tool that will help you do this correctly is Accupel’s display calibrator calculator, from forum member Greg Rogers of Accupel’s. Find it here http://www.accupel.com/HDG4000_manuals.html
[b]Blue not following red/green[b]
Unfortunately I have no answer here. When you look at my calibration files you’ll see in early calibrations that blue takes a significant dip at 60-70% grayscale. Since that is roughly where I slid my white point to with contrast blue is now falling off at white meaning I can now raise the dip with my drives. But this ups the value of blue across the full range, meaning that now R&G cuts need to be increased to fix grayscale on the low end. This raises the black level and also effects the gains a bit requiring blue to be notched up a little on gains, back to the cut, back to the gains and before you know it while grey scale may be improving gamma once again has gone to hell taking your black level with it (almost doubling it from where I started). So you have to give up gray scale accuracy (at least on my 42rv530) in order to get a decent gamma. That’s the compromise I made.
I’m making this enormous post to help other users with similar issues, it’s primarily useful for Toshiba owners as different TV’s have different features (Sharps 6 point gamma RGBs, man what I’d give for 3 point gamma/RGB) and even the same controls (usually color, tint) often work very differently on different TV’s. It’s also a sanity check to make sure I’m not doing anything insane in my calibrations as I’m very much an amateur, and an appeal for help as I’m not entirely happy with the sacrifices I’ve made in the calibration. So if anyone with experience with Toshiba’s can shed some light on things I could do better I’m all ears.
Foot note on calibration(pre calibrated files was actually after a user menu calibration with the spyder, my earlier calibrations where more concerned about grayscale tracking and total contrast than gamma tracking. After seeing the washed out look I went after tweaking the gamma levels).
I used a spyder II, so my results may be a little less accurate but the principles of my calibration should be sound.
Before reading this post you should read this post http://www.avsforum.com/avs-vb/showthread.php?t=852536. It covers the high level concepts in far more detail than I am about to. I’m also going to be light on specific details (xyY, CDM values) and attach several calibration files at the end.
The big issues with my set and I believe many are applicable to at least similar generation Toshibas and previous generation Toshibas if not all LCDs.
1) The gamma starts falling off aft 50%, With the darkest static gamma setting (-5) my set runs about 2.1 gamma, but above 50% the gamma drops (screen becomes brighter, washed out) above that, ending at ~1.7-1.8 gamma at 90% white.
2) The Green primary is misallocated v STMP-E or rec.709 color gamut. It is naturally about dE of 20 away from the rec.709 primary location.
3) Blue simply does not want to track with red and green.
Before we can address these issue we need a better understanding of what controls are available to us via the user and service menus.
User menu:
contrast This essentially is a component of where the signal gets clipped at the high end. Raising it causes the image data to get clipped at a lower value, lowering it preserves image detail. (It also shift the gamma tracking, I'll get into that later).
backlight Kind of a no brainer, this decides how much light should be emitted into the screen, raising it raises and lowers both black level and white level. IMHO the lower you can run your backlight the better off you'll be.
brightness Brightness effects primarily the black level of set, raise it high enough and you can see BTB data being passed. It does increase the brightness somewhat across the whole range of colors.
color The color control is a pretty straightforward color control, it changes the luminance(Y value in xyY) of your colors with minimal effect to grayscale.
tint The tint control also works very well, it changes the hue of the secondaries rotating them on the CIE triangle with very minimal effect to grayscale or primary values.
ADV -- static gamma This control is mapped backwards from the way you'd assume it works based on numerical gamma. -5 is higher gamma number, +5 is a lower gamma number. (-5 yields highest gamma setting).
ADV -- color temp The values are simply offsets for your RGB drive/cuts (get into those in a minute). This means regardless of what you set it to here once you do grey scale the end results are the same. If you calibrate cool to D65, the calibrated cool will exactly match a calibration where you decided to use warm when you calibrated white to D65. I decided that since every setting yields the same result (for that calibrated setting) I would calibrate normal to D65, so if I wanted I could have a cool and warm setting that will shift the color temp up or down (anime, b&w).
ADV -- G & B drives I don't actually recall if they are labeled drives. These two colors are available in the user menu by pressing enter on the color temp then selecting down. These controls map directly to Green and blue drives in the service menu and have the exact effect those controls have. I believe there is no red, because red is the color that clips first in all sane color temperatures, so since it makes more sense to leave it steady and move the other two colors next to it.
Colormaster My set on has "colormaster" and not the pro version which is on the cinema series displays. I have found that these controls actually work very well, the trick is to use the brightness setting as little as possible. +-5 for brightness is fine, in the 5-10 range you'll notice a small amount of macro blocking. I do not recommend setting any brightness over 10 in color master. Hue does what you would think rotating the point around the CIE diagram. Saturation, does do some saturation moving the color closer or further from white, but it also has a profound effect on the colors luminance and I found could be used as sort of a course gain for color luminance.
service menu
Click mute, mute on the remote, hold down mute the second time and press menu on the TV and you're in. (unless otherwise noted 00 is the lowest setting in the service menu and FF is the highest, this is hexadecimal and give you 256 increments).
RGB drives These effect your grayscale on the high end. If you turn them up to high you will begin to blow out the TV’s menu system. These values in combination with the contrast setting determine how much light the TV will actually pass through. I have found no value in trying to run these values higher or lower for calibrating gamma or color. The TV image will be very similar with these values >90 and <70 but above 90 the user menus begin to blow out. These controls are generally fairly sensitive not needing more than 2 or 3 clicks to change a few percentages. These controls interact with brightness, contrast, and RGB cuts.
RGB cuts These effect both the white balance for the low end of your grey scale, but also your black level. These are also unique in that 80 is low and 7F is high, so a setting of 80,80,80 provides the best black point (darkest) while a setting of 7F,7F,7F provides the worst black point (brightest). Blue, our habitual offender, is far and away the brightest color in the low IRE patterns, so leave blue at 80 and balance the Red and Green cut off blue. I found depending on how your calibration is going you may want to sacrifice some grayscale balance in the lower IRE for a better black level. These controls are not very sensitive and will sometimes need to move as many as 20 clicks to move 3-4% when balancing a 30 IRE test pattern. These controls interact with brightness and RGB drives, and to a lesser extent contrast (but not by much).
BRTC, COLC, UVTT I’m ganging these three together because they are very similar. BRTC is brightness center, COLC is color center and UVTT is essentially tint center. These service level controls are essentially moving brightness, color and tint for you across all inputs. Since brightness, color and tint in the user menu are per input, I believe it makes more sense to these values corrected here in the service menu so you do not have to duplicate the most accurate setting across all inputs that you use.
CONTX CONTX is contrast max slides where the top end of the user contrast scale is on the range of contrasts available. It has the exact same effect as setting contrast in the user menu. So if you select contrast of 50 in the user menu and raise the CONTX up enough eventually, even at a user contrast setting of 50 you will start clipping WTW and eventually white below peak white. I set max contrast so that a 100 IRE pattern for video white is just below clipping with white calibrated to D65. I did this since you couldn’t possible make an argument for having the contrast clip into any of the lower IRE patterns and lowering user menu contrast can raise the clipping point to 255 and above easily (and as you’ll see in the next section I had to go way beyond that).
So these are the controls that we can use to tune the display. Now that I have explained what I have found to be the functionality of the display here is what we can do to try and correct the biggest out of the box offenders.
The gamma problem
This is far and away the one of the biggest compromises you’ll have to make. I decided that after setting up contrast so 235,235,235 @ D65 is just barely below clipping with 100 user menu contrast, I lowered user menu contrast all the way down to 50. Because contrast is so low, I also turned my backlight up a bit to 55. What this does is essentially move white down to about where 70% would be on the gamma/rgb levels/grayscale. This allowed me to have an average gamma of just over 2.1 and I was able to get my 90% gamma up to 1.95, much better than where I originally started. But you definitely trade off some dynamic range to get this.
The green problem
Colormaster can only do so much. I moved green to -30 saturation and that seemed to get green as close as possible to rec.709 green. After that you pretty much have to give up on the rec.709 color gamut and calibrate your display to its unique color gamut, the tool that will help you do this correctly is Accupel’s display calibrator calculator, from forum member Greg Rogers of Accupel’s. Find it here http://www.accupel.com/HDG4000_manuals.html
[b]Blue not following red/green[b]
Unfortunately I have no answer here. When you look at my calibration files you’ll see in early calibrations that blue takes a significant dip at 60-70% grayscale. Since that is roughly where I slid my white point to with contrast blue is now falling off at white meaning I can now raise the dip with my drives. But this ups the value of blue across the full range, meaning that now R&G cuts need to be increased to fix grayscale on the low end. This raises the black level and also effects the gains a bit requiring blue to be notched up a little on gains, back to the cut, back to the gains and before you know it while grey scale may be improving gamma once again has gone to hell taking your black level with it (almost doubling it from where I started). So you have to give up gray scale accuracy (at least on my 42rv530) in order to get a decent gamma. That’s the compromise I made.
I’m making this enormous post to help other users with similar issues, it’s primarily useful for Toshiba owners as different TV’s have different features (Sharps 6 point gamma RGBs, man what I’d give for 3 point gamma/RGB) and even the same controls (usually color, tint) often work very differently on different TV’s. It’s also a sanity check to make sure I’m not doing anything insane in my calibrations as I’m very much an amateur, and an appeal for help as I’m not entirely happy with the sacrifices I’ve made in the calibration. So if anyone with experience with Toshiba’s can shed some light on things I could do better I’m all ears.
Foot note on calibration(pre calibrated files was actually after a user menu calibration with the spyder, my earlier calibrations where more concerned about grayscale tracking and total contrast than gamma tracking. After seeing the washed out look I went after tweaking the gamma levels).