Author Topic: Greyscale/Gamma Calibration Tip  (Read 5674 times)

Offline idm

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Re: Greyscale/Gamma Calibration Tip
« Reply #15 on: October 15, 2015, 06:06:20 AM »
I do apologize, but I used to have the same opinion until I got a spectro. There is definitely benefit in it.

Offline KenMasters

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Re: Greyscale/Gamma Calibration Tip
« Reply #16 on: October 15, 2015, 08:15:50 AM »
I do apologize, but I used to have the same opinion until I got a spectro. There is definitely benefit in it.

I have no doubt, but at R15 000 for an i1 Pro 2 benefit vs cost is the question. Is it just for calibrating your E6500?
« Last Edit: October 15, 2015, 08:30:24 AM by KenMasters »

Offline KenMasters

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Re: Greyscale/Gamma Calibration Tip
« Reply #17 on: October 15, 2015, 04:12:26 PM »
Chromapure's compensation values for the variance across display types for the i1display Pro (2012):

« Last Edit: October 15, 2015, 04:15:03 PM by KenMasters »

Offline idm

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Re: Greyscale/Gamma Calibration Tip
« Reply #18 on: October 16, 2015, 06:15:19 AM »
Chromapure's compensation values for the variance across display types for the i1display Pro (2012):



That's an awesome find. I will check and compare with the pro2. It is just for the 6500 and some other display's of friends and family. If you are local to me, I am willing to give you a demo, I am in Boksburg Gauteng.

Offline KenMasters

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Re: Greyscale/Gamma Calibration Tip
« Reply #19 on: October 16, 2015, 01:20:14 PM »
That's an awesome find. I will check and compare with the pro2. It is just for the 6500 and some other display's of friends and family. If you are local to me, I am willing to give you a demo, I am in Boksburg Gauteng.

Bear in mind this is for their own calibrated "Display 3 PRO II". Any plans to upgrade your display?

Sorry, I no longer live in S.A. and when I do come down it's to CT.
« Last Edit: October 16, 2015, 01:31:09 PM by KenMasters »

Offline idm

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Re: Greyscale/Gamma Calibration Tip
« Reply #20 on: October 16, 2015, 01:55:01 PM »
No upgrade's for the moment, I like the plasma display's but they are/have been taken off the market. When I do it will probably be a lcd, but I'll do my homework properly on what model to buy before doing so.

Offline KenMasters

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Re: Greyscale/Gamma Calibration Tip
« Reply #21 on: October 16, 2015, 06:31:04 PM »
No upgrade's for the moment, I like the plasma display's but they are/have been taken off the market. When I do it will probably be a lcd, but I'll do my homework properly on what model to buy before doing so.

Not keen on OLED? Panasonic's processing has done a lot to clean up issues with the LG panels and apparently they have a knowledge sharing agreement with LG's panel division. From the CZ952 reviews I've looked at it's just the low level banding that's still an issue. I would like to see someone implement some form of dark frame insertion/scanning as the motion resolution drop is bothersome to me. Although the Panasonic LCDs are looking very impressive - you know their higher tier colour processor uses an 8000 point 3D LUT - very consistent panels across all saturations.

I know I'm a bit of a Panasonic fanboy, but they're pretty much the only manufacturer that really pays attention to the smaller picture quality details, they have a game mode that doesn't affect quality and I love using DDC for calibration. Though Sony is a close second, very impressive out the box performance on their sets, I just wish they were more calibration friendly. Sorry to prattle on, just not many on the forum that are into TVs.

Offline idm

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Re: Greyscale/Gamma Calibration Tip
« Reply #22 on: October 17, 2015, 08:28:42 AM »
Does the Panasonic 3d 8000 point lut allow for cal of all 8000 points? Does Calman allow for it? What is the average price of it? That is interesting, I will strongly consider it when I do upgrade.

No problem prattling on, another one of my deep interests

Offline KenMasters

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Re: Greyscale/Gamma Calibration Tip
« Reply #23 on: October 17, 2015, 11:17:43 AM »
Does the Panasonic 3d 8000 point lut allow for cal of all 8000 points? Does Calman allow for it? What is the average price of it? That is interesting, I will strongly consider it when I do upgrade.

The Accurate Colour Drive as they call it does all the heavy lifting, you just need to set the primary and tertiaries and the tables are accurately updated across the board (as demonstrated in review measurements). Price depends on the model.

Some of the Sony and Panasonic panels are so accurate out the box they hardly need calibration (sometimes just a nip and tuck on the 2 point greyscale). My own panel's THX mode is fairly spot on out the box, but I don't care for the 2.2 gamma. Actually curious, how did you deal with setting the gamma given your panel's floating blacks? My old V20 used to do the same, was not an easy task getting it to my liking.

I don't know if you're familiar with DDC, on the Panasonics you can calibrate the set through the CalMAN interface alone, no fussing with the remote and on screen menus.
« Last Edit: October 17, 2015, 11:32:59 AM by KenMasters »

Offline idm

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Re: Greyscale/Gamma Calibration Tip
« Reply #24 on: October 18, 2015, 03:24:03 PM »
On my panel, I leave the gamma at 0 and adjust cuts and gains as minimal as possible, do not lower the low end, only adjust red and blue up or down on the high end. The outcome is a quite flat 2.2 gamma. Then when calibrating the lut I aim for about 2.35 rec709, outcome is pretty good. What I Found is best for the i1d3 is to set a white balance of d55 for warm 2 and then change the colour temperature of the display to warm 1 and then measure the colour temp from calman and use that for calibration.

The reason being is that both the i1d3 and i1pro2 are both factory calibrated for d55, usually the display's warm 1 is exactly 1000 kelvin above warm1 re: 7500k and the internals will make a proper conversion as to the colour temp.Try it, you may be surprised.

Offline KenMasters

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Re: Greyscale/Gamma Calibration Tip
« Reply #25 on: October 18, 2015, 07:25:19 PM »
On my panel, I leave the gamma at 0 and adjust cuts and gains as minimal as possible, do not lower the low end, only adjust red and blue up or down on the high end. The outcome is a quite flat 2.2 gamma.

Okay, so your panel has a 2 point adjustment and no gamma/luminance adjustment. Unless you were very careful with your pattern choice (I had to make my own) and Contrast setting, the gamma reading would not be accurate due to the black level shift (though accurate is relative when discussing plasmas).

 
Then when calibrating the lut I aim for about 2.35 rec709, outcome is pretty good.

When you say Rec. 709, do you mean BT.1886 or power law?

 
What I Found is best for the i1d3 is to set a white balance of d55 for warm 2 and then change the colour temperature of the display to warm 1 and then measure the colour temp from calman and use that for calibration.

The reason being is that both the i1d3 and i1pro2 are both factory calibrated for d55, usually the display's warm 1 is exactly 1000 kelvin above warm1 re: 7500k and the internals will make a proper conversion as to the colour temp.Try it, you may be surprised.

Not sure I follow you, if you're saying one should ignore what CalMAN is telling you, I can't agree. Knowing what D65 looks like, CalMAN's reading is accurate.
« Last Edit: October 18, 2015, 07:38:42 PM by KenMasters »

Offline KenMasters

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Re: Greyscale/Gamma Calibration Tip
« Reply #26 on: October 19, 2015, 12:55:58 AM »
Okay, so your panel has a 2 point adjustment and no gamma/luminance adjustment...

I mean multpoint adjustment.

Unless you were very careful with your pattern choice (I had to make my own) and Contrast setting,,,

I forget, on a Samsung plasma it's Cell Light that controls light output.

Offline idm

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Re: Greyscale/Gamma Calibration Tip
« Reply #27 on: October 19, 2015, 07:46:41 AM »
My display has a 10 point gamma adjustment and a cms that works well, but I prefer to let the ee color box sort that out. Colour space target is rec709, gamma that I use is power law. Brightness and contrast is pretty good out of the box, contrast can be toned down a bit. I am using Ted's light space cms disk for patterns, also have spears and munsell hd benchmark second edition, I just use the spears for reference.

Okay, if you set the white balance to d65/rec709 with the colour temp set to warm 1, and then change it to warm 2, if your meter is accurate for d65 you will have an accurate d55 at warm 2. If not, set warm 2 to d55 accurately, change the colour temp to warm 1, measure/capture the colour space in the colour space editor of calman, save it. Now you can calibrate warm 2 at d65/rec709 using the colour space you have just captured, just leave the chromaticity coordinates as rec709/srgb. The i1display pro is more accurate at d55. Actually the i1pro2's ref tile coordinates is x=0.33333 y=0.33333 this amounts to a temp of close to 5500k. I have tested this, by setting d65 with the pro2 and then checking the colour temp with the display pro and they do not agree at d65. When done at 5500k the agreement is a lot closer, only that the display pro over reads (not enough)  blue by a small amount, about one click.

What technology display are you using, what meter mode do you use? The above mentioned method is true for the plasma meter mode as my display is plasma. I have tried all the different modes available for it, and the plasma proves to be the most accurate for my display.

Offline KenMasters

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Re: Greyscale/Gamma Calibration Tip
« Reply #28 on: October 19, 2015, 08:42:21 AM »
My display has a 10 point gamma adjustment and a cms that works well, but I prefer to let the ee color box sort that out. Colour space target is rec709, gamma that I use is power law.

You should consider switching over to 1886, works brilliantly if you can manage to implement it properly - and it is the standard now. Power law's not great for low end detail, 1886 is a better solution for mimicking the EOTF of a CRT as your black level is taken into account. You might end up coming out of black closer to 2.2 (for example) then level out through the mid and high range at 2.4. Best of both worlds.

Okay, if you set the white balance to d65/rec709 with the colour temp set to warm 1, and then change it to warm 2, if your meter is accurate for d65 you will have an accurate d55 at warm 2. If not, set warm 2 to d55 accurately, change the colour temp to warm 1, measure/capture the colour space in the colour space editor of calman, save it. Now you can calibrate warm 2 at d65/rec709 using the colour space you have just captured, just leave the chromaticity coordinates as rec709/srgb. The i1display pro is more accurate at d55. Actually the i1pro2's ref tile coordinates is x=0.33333 y=0.33333 this amounts to a temp of close to 5500k. I have tested this, by setting d65 with the pro2 and then checking the colour temp with the display pro and they do not agree at d65. When done at 5500k the agreement is a lot closer, only that the display pro over reads (not enough)  blue by a small amount, about one click.

I don't understand what you're trying to achieve by doing this, too many variables to just go by the numbers. At any rate, my display only has one warm setting.

What technology display are you using, what meter mode do you use? The above mentioned method is true for the plasma meter mode as my display is plasma. I have tried all the different modes available for it, and the plasma proves to be the most accurate for my display.

I've got a 55" Panasonic VT60 and use the plasma metering mode. Helpfully I also have a D65 Philips Graphica backlight and D65 wall paint.
« Last Edit: October 19, 2015, 08:51:35 AM by KenMasters »

Offline idm

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Re: Greyscale/Gamma Calibration Tip
« Reply #29 on: October 19, 2015, 09:13:44 AM »
What I'm trying to achieve here and I am achieving is getting accurate readings for d65, overcoming the inaccuracies of the meter at d65. If you only have one warm setting try standard, if it's 7500k then it will work as well. You cant get an accurate bt1886 with a 2point, even a 10 point white balance control, anything up from 21 point will get you more or less in line with it.