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Discussion Starter · #1 ·
Calibration question here for you guys - hope this is straight-forward.


I have a Sharp 10000 that is fantastic. I've just recently started playing with calibration using AVIA/VE. I have its color temp set at 6500.


I am currently using a cheap-o $99 Panasonic DVD player from Best Buy via component output at 480i while I await my real DVD player.


I am using the trick of looking for noise in the black dithering at the screen to determine the best brightness setting. This works great and is easy to determine.


With this DVD player and the Sharp 10K I've determined that the brightness should be set at +1.


My problem comes when setting contrast - according to several different approaches, the correct contrast setting for me is +3. However, when I look at the grayscale after setting contrast to +3 the 90 IRE level has a fairly strong pinkish color. 100IRE and 60-80 IRE pick up some of this pink as well. And the pink is not noticeable from o-50 IRE.


With the little I know about grayscale, I know enough to realize that with this pinkish error in the grayscale it will certainly affect my color accuracy.


Interestingly NOTHING I change in my settings, with the exception of lowering contrast, will remove the pinkish color. This is quite concerning.


For example, I tried changing the color setting +/- all the way, the Red Gamma +/- all the way, the Red Offset +/- all the way, and the Red Gain +/- all the way. I even tried moving the Color Management System sliders for Red luminance, saturation, and hue +/- all the way. The pinkish color stays constant. While writing this I realized that I didn't try moving the tint at all, which is currently set at -1 along with color at -2 from my blue filter color tests on AVIA.


Now if I lower the contrast back toward 0, most of this pinkish color goes away. If I take it down to -5, then I have true gray throughout the grayscale.


I also am very confident that, pink coloring aside, +3 is the correct contrast setting - as writes do not begin to crush until +4.


In case it matters - I used two different techniques to come up with the +3 contrast setting. First I set the brightness as mentioned above. Then with the first technique I use the AVIA test pattern for contrast which gives me +3 at the point where the lighter bar disappears. With the second technique, I put up a 100 IRE pattern and increase contrast one click at a time until it does not get any brighter. This occurs when I click from +3 to +4 so I know +3 is the setting.


Is this sort of thing normal? I am wondering whether its possible that I have a problem with my particular Sharp 10000. Normally I wouldn't be too concerned because I'd assume a true ISF calibration would resolve it. However it is concerning that despite my changing all of the possible settings the pinkish color would not go away until I lowered contrast.


I was wondering if it is also possible that this is an error being introduced by my el-cheapo DVD player. Actually I call it a cheapo since it was only $99 to hold me over, but its probably quite similar to the RP62 minus some features and the RP62 is fairly well respected I believe.


Any thoughts or tips on things to try would be helpful. For example, I'd like to tweak it so that I can get the contrast where it belongs yet still have a nice looking (by-eye) grayscale. Eventually I will calibrate or have an ISF calibrate via professional tools but I'd like to resolve this in the meantime.


Thanks!
 

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If your display looks pink at 100 ire, then you are running out of GREEN. i.e. White - Green = Magenta (pinkish). So to fix it, you can add some Green, or reduce Red and Blue (which you are doing by lowering contrast) Same thing applies to your mid-level IRE's. Your Green Gamma curve is not tracking (increasing) at the same rate as red and blue gamma curve.


I don't own your particular projector, so I can not tell you what control to adjust, but if you have green bias/gain controls, I would adjust those a little, that should add some green, and push the green gamma curve up. If you do not have controls for green (or are really out of green), then you will have to fix it using the red and blue controls.


Just a thought, good luck.
 

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Discussion Starter · #3 ·
Quote:
Originally posted by John Nelson
If your display looks pink at 100 ire, then you are running out of GREEN. i.e. White - Green = Magenta (pinkish). So to fix it, you can add some Green, or reduce Red and Blue (which you are doing by lowering contrast) Same thing applies to your mid-level IRE's. Your Green Gamma curve is not tracking (increasing) at the same rate as red and blue gamma curve.


I don't own your particular projector, so I can not tell you what control to adjust, but if you have green bias/gain controls, I would adjust those a little, that should add some green, and push the green gamma curve up. If you do not have controls for green (or are really out of green), then you will have to fix it using the red and blue controls.


Just a thought, good luck.
Thanks John. I was thinking that it looked pinkish because of too much red but what you said makes perfect sense.


The only odd thing is that the pinkish color was much more pronounced at 90 IRE compared to 100 and 60-80 (although still present there). Likewise there was no visible pink in 50 IRE and below. Is this a function of the gamma curve?


On the Sharp 10000 I have separate adjustments for gamma, gain, and offset for red, blue, and green.


I'll try expirementing. Any feel for what may be the best combinations to try? For example, because the issue seems mainly about 50 IRE would that be green offset or green gain that needs to be increased? I recall that offset controls the higher or lower IREs (can't recall which) and that gain controls the other IREs.


So I will likely need to increase either the gain or offset of green (again depending on which controls the upper IREs) and then increase (or decrease?) the green gamma to compensate for the fact that the green error (lack of green) is only in the 60+ IRE range. Correct?
 

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I think you have it, set the black point with the offset controls, set white point with the gain controls, then adjust the middle with the gamma controls. That's basicly what I do on my G15, might work on yours. Good Luck.
 

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I think the reason your grayscale is going pink is that on the highest levels of white the projector is running out of green and blue. When you increase the contrast past a certain point then the blue and green outputs are saturating before the red therefore making the greyscale look pink. The only answer in ths case is to reduce the contrast back until white is achieved.


Regards

Zaphodgbr
 

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If your dvd is connected via component ....disconnect the Red and Blue cables. You'll get a monochrome image with no color signal. Then ..using the Avia IRE's try adjusting your your rgb controls for a good gray scale. Gain is for the IRE's above 50 and Bias or cutoff are for IRE's below 50. Go back and forth trying to get the best and same gray and in all IRE's without ANY color tint. Gamma shouldn't effect color. You can't do this accurately without a color meter but but you can get very close by eye.
 

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"I understand that the light source used by the sharp and others produces more red than other colors therefore when you increase the contrast past a certain point then the blue and green outputs will saturate before the red therfore making the greyscale look pink."


Unless Sharp is using a new kind of bulb like no one else's, it is red deficient. Sharp might have chosen to do it right and use filters to give optimum color rather than maximum brightness, along with an inherent red bias with a new bulb that moves to optimum after the frist 50-100 hr (SHP and UHP bulbs lose a significant amount of red output early in their life).
 

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Discussion Starter · #8 ·
Quote:
Originally posted by JimmyR
If your dvd is connected via component ....disconnect the Red and Blue cables. You'll get a monochrome image with no color signal. Then ..using the Avia IRE's try adjusting your your rgb controls for a good gray scale. Gain is for the IRE's above 50 and Bias or cutoff are for IRE's below 50. Go back and forth trying to get the best and same gray and in all IRE's without ANY color tint. Gamma shouldn't effect color. You can't do this accurately without a color meter but but you can get very close by eye.
Thanks for the tip. Is disconnecting red and blue and different than setting the color control all the way down? Also why is this step necessary, as opposed to just adjusting grayscale with all cables in and color set as normal - I would think adjusting rgb this way would be more indicitive of real-world scenario.
 

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Discussion Starter · #9 ·
OK, I tried a few experiments last night but didn't get too far...


Since it was suggested here that perhaps I didn't have enough green, first I tried playing with the green gain, green offset, and green gamma. No tweaks there has any effect on reducing the pinkish color I'm having particularly at 90 IRE.


After some logical and many random combinations between all three color gain, offset, and gamma settings I came to the conclusion that nothing I was doing was able to effectively remove the pinkish color from 90 IRE. It was a bit frustrating because I felt like I was just shooting in the dark with random combinations when moving the adjustment sliders.


In the process of this tweaking however I did manage to make the overall grayscale more gray. For example the default grayscale at 6500 is a bit on the reddish/brown side.


I was able to achieve the better overall grayscale by reducing red gamma to -2, green gamma to -3, green offset to -5, and *increasing* blue gamma to 3. Now the grayscale particularly at and below 50 IRE was a more definitive gray. But the upper IREs and 90 IRE in particular still have a pinkish tone.


I must say that with these settings the colors on the DVD seem more vibrant and true. When doing A/B comparisons between my original settings and these tweaked settings it becomes obvious that the original settings had a bit too much green.


Also I tried these tweaks both with and without the red and blue components cables plugged in and there was no difference.


Any thoughts on what else I can try to remove the pinkish tones?
 

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Ok, since it is a competitor, I should stay quiet, but...


What has happened is that you have reached the point of White Crush in green. Very rarely will all three colors reach the crush point at the same time. Since in this case green is the limiting factor, you have to set your peak contrast at the point where the picture starts to color shift. This will limit your peak brightness a bit, but yield the flattest gray scale. Nothing else will work. If green (typically the most transparent of the 3 colors in the wheel) has had it, then you have to back down red and blue (which in this case can only be done by backing down the contrast).


The easiest way to do this is to do the THX optimode contrast pattern or the black/white needle pulse (with black and white pluge signals) from AVIA using only green. This might not be easy to accomplish; one way is to transcode the component out of the dvd to RGB and use only the G cable. Another is to connect a PC and create a green pluge (say 94, 96, 98, and 100% saturation) test pattern in something like powerpoint or photoshop.


Lacking those, use the THX or AVIA patterns and turn up the contrast until you see the color start to shift. Stop there.


DM
 

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Discussion Starter · #11 ·
Quote:
Originally posted by Dan Miller
Ok, since it is a competitor, I should stay quiet, but...


What has happened is that you have reached the point of White Crush in green. Very rarely will all three colors reach the crush point at the same time. Since in this case green is the limiting factor, you have to set your peak contrast at the point where the picture starts to color shift. This will limit your peak brightness a bit, but yield the flattest gray scale. Nothing else will work. If green (typically the most transparent of the 3 colors in the wheel) has had it, then you have to back down red and blue (which in this case can only be done by backing down the contrast).


The easiest way to do this is to do the THX optimode contrast pattern or the black/white needle pulse (with black and white pluge signals) from AVIA using only green. This might not be easy to accomplish; one way is to transcode the component out of the dvd to RGB and use only the G cable. Another is to connect a PC and create a green pluge (say 94, 96, 98, and 100% saturation) test pattern in something like powerpoint or photoshop.


Lacking those, use the THX or AVIA patterns and turn up the contrast until you see the color start to shift. Stop there.


DM
Thanks. A few follow up questions please:


1) You say "then you have to back down red and blue (which in this case can only be done by backing down the contrast)."


Why is it that red and blue can only be backed down by reducing contrast? I have separate controls for red, green, and blue for gamma, gain, and offset. Couldn't I use these controls some how to back down red and blue without having to back down contrast?


2) How do I transcode the component out of the dvd to RGB? What type of part do I need for this?


3) Where on AVIA is the THX optimode contrast pattern? What does this pattern look like?


4) The Sharp outputs 800 lumens in high brightness mode and 500 lumens in high contrast mode with the iris function. There is also a Power Save mode that reduces lightout by 20%.


I am currently running in high contrast mode with Power Save off. One thing I am considering is going to high brightness mode, and then using Power Save mode. This should result in 640 lumens which is a bit brighter than the 500 I currently use.


I'm thinking that because I have to reduce the contrast to stop the color shift, that perhaps I can achieve about the same brightness using high power with Power Save on and contrast at the lower setting.


Does that sound like it would help me? Thanks!
 

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1. By using the gain controls for red and blue, you are in effect lowering the contrast, because green has already reached the point of maximum output. This of the bias and gain controls as brightness and contrast for the individual color.


2. I use an Extron CVC200. Inline and key digital also make one (to name a few)


3. I meant the THX OptiMode pattern (available on any THX certified DVD since SW Episode 1, or the B/W patterns on AVIA.


4. If their High Bright mode is like ours, it will screw up color. Primarily designed for presentations. High and low power are for bulb life and power concerns (not really a big difference).


You are right using high bright off, high contrast on, and power save off. Ultimately you decision will be about less peak brightness vs. gray scale accuracy. Just like a CRT. Maybe use a 90 IRE pattern and go for gray scale accuracy to that point and let 100 go a little pink. You might not notice it then on real world pictures.


DM
 

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Discussion Starter · #13 ·
Quote:
Originally posted by Dan Miller
1. By using the gain controls for red and blue, you are in effect lowering the contrast, because green has already reached the point of maximum output. This of the bias and gain controls as brightness and contrast for the individual color.


2. I use an Extron CVC200. Inline and key digital also make one (to name a few)


3. I meant the THX OptiMode pattern (available on any THX certified DVD since SW Episode 1, or the B/W patterns on AVIA.


4. If their High Bright mode is like ours, it will screw up color. Primarily designed for presentations. High and low power are for bulb life and power concerns (not really a big difference).


You are right using high bright off, high contrast on, and power save off. Ultimately you decision will be about less peak brightness vs. gray scale accuracy. Just like a CRT. Maybe use a 90 IRE pattern and go for gray scale accuracy to that point and let 100 go a little pink. You might not notice it then on real world pictures.


DM
Thanks Dan. Rather than going through any trouble/expense to get a transcoder, I was wondering either either of these two approaches would work equally as well....


a) With the Sharp 10K you tell it whether the RGB inputs on the back of the unit are being used with component or RGB signals. I use component and mistakenly I hit the button on the remote that switched it to RGB. The result was that my entire picture went completely green. Would this effectively give me the same result as the transcoder? I was thinking that perhaps I could just use the component feed, tell the pj it was an RGB signal, and then use the B/W test patterns to dial in brightness and contrast using only the green.


b) Or if the above will not do the trick, could I just turn the red and blue gain and/or offset all the way down and effectively remove all the red and blue from the image. Then calibrate using just green this way? If so, all I need to do is just turn these all the way down? Do I need to do gain and offset or just one or the other?


Assuming one of these approaches does the trick, what do I do exactly? Just calibrate brightness and contrast as I would normally, except I'll only have green on at the time?


What will this result give me exactly? The point where all three colors are maximized just prior to green crush? From there would I need to use red and/or blue gain/offset controls to dial things in further?


Thanks!
 

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DUH! (slaps self in forehead---OUCH!)


Why didn't I think of that? I have made the same mistake more times that I can count. You can absolutely set the component to RGB and look at the green image. Or... Maybe use a breakout cable (VGA to 5x BNC) and use just the green cable from the Y output of component from DVD (really the same thing).


That should work fine.


Ultimately though, backing down the contrast will yield exactly the same result. Turning sown red and blue is bringing their contrast down to meet green. The problem that might arise when using the drive controls is it might mess up the gamma curves for those colors. Save yourself trouble and use the contrast control.


DM
 

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Discussion Starter · #15 ·
Quote:
Originally posted by Dan Miller
DUH! (slaps self in forehead---OUCH!)


Why didn't I think of that? I have made the same mistake more times that I can count. You can absolutely set the component to RGB and look at the green image. Or... Maybe use a breakout cable (VGA to 5x BNC) and use just the green cable from the Y output of component from DVD (really the same thing).


That should work fine.


Ultimately though, backing down the contrast will yield exactly the same result. Turning sown red and blue is bringing their contrast down to meet green. The problem that might arise when using the drive controls is it might mess up the gamma curves for those colors. Save yourself trouble and use the contrast control.


DM
Thanks Dan. So now that I know how to get green only output, what are my exact steps to take again? The way I currently understand it is that I should set brightness and contrast as I would normally, except using green output only. Then look at the grayscale and it should be nice and gray (no pinkish color).


Normally I set contrast by putting up a 100 IRE field and increasing one click at a time until the 100 IRE field does not get any brighter. Is it safe to assume I can use this same technique with green only, except that I'd increase it until the green field doesn't get any brighter?


Likewise since this is a DLP unit, I've been setting brightness by standing at the screen and finding the highest point where I no longer see dithering in the blacks. So I assume I can do this using green only just the same? The only issue I've found with this technique is that when seated far away you cannot see material just above black which results in some black crush. So I typically set the contrast a couple of clicks above the point where the dithering stops.


Anyway to make a long story short, should I be setting brightness with all three colors and contrast with only green, or should I be setting both brightness and contrast with only green?


Thanks!
 

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Well, two ways that I use:


1. THX optimode (although some say that it is only good for the disc in question, I haven't found that to be true). The first pattern in the test patterns (btw... use only THX certified DVD's released since Episode 1 Star Wars, since the older ones don't have the pattern in question) has 8 blocks on the screen consisting of 4 high IRE values, 94, 96, 98, and 100. By increasing the contrast until 98 and 100 just blend and then backing it down until they can be seen distinctly, you have it.


2. The black and white level setting patterns on AVIA have moving high IRE bars on a 100 IRE background. Same concept as above.


Black level will be with all colors, unless you see color shift toward the low end, in which case you have no choice but to use the cutoff or bias controls.


Have FUN!


DM
 

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Discussion Starter · #17 ·
Quote:
Originally posted by Dan Miller
Well, two ways that I use:


1. THX optimode (although some say that it is only good for the disc in question, I haven't found that to be true). The first pattern in the test patterns (btw... use only THX certified DVD's released since Episode 1 Star Wars, since the older ones don't have the pattern in question) has 8 blocks on the screen consisting of 4 high IRE values, 94, 96, 98, and 100. By increasing the contrast until 98 and 100 just blend and then backing it down until they can be seen distinctly, you have it.


2. The black and white level setting patterns on AVIA have moving high IRE bars on a 100 IRE background. Same concept as above.


Black level will be with all colors, unless you see color shift toward the low end, in which case you have no choice but to use the cutoff or bias controls.


Have FUN!


DM
Since I don't have a THX certified receiver I've never paid much attention to which of my DVDs are THX certified.


I do recall however that Monsters, Inc. has a cool little presentation when it first starts up that says its THX Certified. Do you think this disc has the THX optimode patterns on it? I don't recall see them but never specifically looked either. Maybe it is on the bonus disk (disk 2)?


In case I can't find it, is there anywhere on AVIA or VE that they have IRE steps less than 10 IREs apart? I really like the idea of having them just a couple of steps apart like you describe the THX optimode pattern has.


Grayscale at my lower IREs didn't have much pink in it. It looked fairly gray but did look like it had some brown in it. Would a lack of green at lower IREs cause it to look a bit brown? If so then it may be running out of green there too and I'll just use green for brightness and contrast.


Is it a safe assumption that using something like ColorFacts takes all this guess work and mystery out of the calibration, and it would be fairly easy to use to get all this adjusted?


BTW, on a related note - do you know if there are any patterns on AVIA or VE that I can use to properly set my lumenance, chrom, and hue specifically for Red? The Sharp has a Color Management System that gives you this level of control and its obvious that reds are too hot/flurecent out of the box. I'd dropped red chroma and raised red hue to make my reds look more realistic, but that's just by eye. I was hoping there is a test pattern I can use with a red filter or something like that to dial in red more scientifically.


Thanks!
 

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Colorfacts... YEP!


All THX certified DVDs have the patterns. THX certifications just means that they were supposedly monitored to make sure that things were done properly during mastering.


On the discs (SW Ep1 and 2, Moulin Rouge, Monsters, Pearl Harbor, and many others...) go to (usually) options, then look for the THX logo and highlight and select that.


On AVIA, go to Black and White levels and use any of the patterns there. On the needle pulse patterns for example, on the top is 100 IRE with 2 moving bars of slightly less amplitude and on the bottom is full black with the same 2 bars at slightly above black.


You can use the color setup part of avia to dial in all three colors relative to each other. My copy of AVIA had filters for all 3 colors...


DM
 

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I found color facts to be a great help in getting this right with the HT1000.


I set the red contrast at a reasonable maximum value as determined by "crushing at high IRE' levels.


I then set the blue and green contrast to match for a temp of 6500 at 80 IRE and then did the same at 25 IRE with the RGB brightness controls. I then used the "color level" which on the NEC gives you RGBCYM and gain to set 50 IRE for 6500.


At the cost of little bit of overall contrast ratio I now have a flat (+/- 50 degrees) 20-90 IRE curve with an overall gamma of 2.0.


The results were worth the effort smooth colors, better detail, and much improved yellows.


Joel


PS: these settings change as the bulb ages so I touch up every 50 -100 hours or so.
 

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Hey lovingdvd, how are you making out with your adjustments? Have you come up with any final #s. I have been following your posts all the way. I would love for you to post your final findings if you would to see how they compare to mine. Thanks
 
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