Basic Guide to Color Calibration using a CMS (updated and enhanced) - Page 68 - AVS Forum | Home Theater Discussions And Reviews
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post #2011 of 2031 Old 01-10-2019, 11:52 AM
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Originally Posted by jowicrt View Post
If i recall correctly, there is an issue with the Kuro 9G (EU) series where under ISF mode, the drivemode can not be changed and is fixed to 75Hz (actually, that should be 72hz, 3x 24...) It can not be changed to 100 for 50hz material or 60 for 60hz. The Kuro returns XXX (error) when doing this in ISF mode. For 50/60Hz material (daytime viewing, news etc) the '75' drivemode causes stutters in panning scenes. That is why i'm only using ISF modes for 24Hz material.
Using Drive mode 2 and Pure mode @ Advanced, you will have correct any input frame rate, the table below is Flicker analysis using Klein K-10A:


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post #2012 of 2031 Old 01-10-2019, 12:24 PM
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No, the problem is that in ISF mode, the drivemode is FIXED at drivemode 1 (72hz). It can not be changed.
Drivemode 1 will give issues with 50/60 hz material, regardless of the movie mode (std smooth advanced etc).

In PURE mode you can set drivemode to 72, 100 or 60 hz.

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post #2013 of 2031 Old 01-10-2019, 01:06 PM
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Originally Posted by jowicrt View Post
No, the problem is that in ISF mode, the drivemode is FIXED at drivemode 1 (72hz). It can not be changed.
Drivemode 1 will give issues with 50/60 hz material, regardless of the movie mode (std smooth advanced etc).

In PURE mode you can set drivemode to 72, 100 or 60 hz.

To the 500A/600A/6090H/5090H (all EU) its not locked the drive mode to the ISF mode, probably its locked to the model you have.

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post #2014 of 2031 Old 01-10-2019, 01:07 PM
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Originally Posted by ConnecTEDDD View Post
A grayscale sweep (grayscale only) will measure 21-Point Grayscale, can you post a picture example of the measurements you have taken?
After calibration, I was able to get the Red delta E down to around 6 in the lower grey readings. Tweaking my RGB bias was making the delta E for Red even worse, this was the best result I could get with rgb gain/bias. This with Rec 709 with 2.4 ganma at a D65 white point.
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post #2015 of 2031 Old 01-10-2019, 01:14 PM
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Originally Posted by brandon_k_w View Post
After calibration, I was able to get the Red delta E down to around 6 in the lower grey readings. Tweaking my RGB bias was making the delta E for Red even worse, this was the best result I could get with rgb gain/bias
The dE chart don't show the RGB channel errors, its 3 colored lines, as per manual describe: https://www.lightillusion.com/profiling_manual.html

The green line is Delta-E 1976, the blue line is Delta-E 2000, and the red line is Delta-E ICtCp (raw value with 240 scalar number).
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post #2016 of 2031 Old 01-11-2019, 04:03 AM
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Originally Posted by ConnecTEDDD View Post
To the 500A/600A/6090H/5090H (all EU) its not locked the drive mode to the ISF mode, probably its locked to the model you have.
Maybe there is a difference between the 500A/600A and the 500M/600M models. I know for a fact that the M models have a fixed drivemode 1 (72Hz) under ISF.
I've did some test to see if the PureCinema modes under ISF would make a difference, but they don't. On the M models, ISF mode only works properly for 24hz material.

But let's not go into that here any further, it is offtopic.

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post #2017 of 2031 Old 05-02-2019, 08:19 AM
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Is there an updated recommendation for a color analyzer? This seems like it might make for a fun summer project once it's too hot to go outside

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post #2018 of 2031 Old 05-05-2019, 03:18 PM
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Originally Posted by J_P_A View Post
Is there an updated recommendation for a color analyzer? This seems like it might make for a fun summer project once it's too hot to go outside
For most users, the i1Pro2 and the i1Display Pro are going to be the optimal choices.

For the i1Pro 2 (if just getting the i1Basic 2 which is same device but fewer other elements), that may get a bit costly as they currently sell for $1200-1350 now many places. This is a spectrophotometer that reads in 10nm wavelengths the color spectrum, but can be put in a higher detail mode which is around 3.5nm wavelengths. This will be fine for most users, but if you absolutely need more detail, you would need a CR-250 for about $6000 (IIRC), a Jeti for around $9000+, or even more expensive reference equipment. You can also pick up a used i1Pro 2 on ebay if needed.

For the i1Display Pro, you will want to pick up a 2018 or newer model OEM variant which can read to 2000 nits. This is a colorimeter, not a spectroradiometer/spectrophotometer. These are better at luminance readings and use tri-stimulus filters that more approximate how the human eye sees color. This can be purchased for $200-300 usually.

For more information on the two recommended color analyzers, you can go to X-rites' web page or review Ted's page discussing both of those products. https://www.displaycalibrations.com/...ions_info.html

Another option, instead of buying the spectrophotometer is to contact a local calibrator with reference grade equipment. He or she will be able to create a CCSS spectral profile of the display with the reference spectrometer and can create a colorimeter correction matrix compared to a reference colorimeter like a Klein K10-A. With the spectral profile and the colorimeter correction matrix to use with your i1Display Pro, you will be able to do an excellent profile and calibration of your display. You will need a CCSS for each display you plan to calibrate, including monitors for your computers and laptops, so you may want to count up what you want them to do a CCSS for and work out the pricing ahead of time.

Then there is the matter of patterns. Some programs have an in-built pattern generator. But, due to the complexities of where errors can occur, you may want, at minimum, to get something like Ted's disc or R. Masciola's patterns to have something to compare the pattern generator to, as missing a setting in Nvidia's control panel or MadVR or any of the other options there are could introduce errors, before discussing the problems with HDMI port inaccuracies, etc. For Nvidia's control panel, there are two places you need to go to set the range for output. First, go to Video>Adjust video color settings, then switch to with Nvidia settings, go to the advanced tab, then set that to Full (0-255).

The Second one is under Display>Change Resolution. Here is where you should select the output color format (RGB or YCbCr) and the Output Dynamic Range (full or limited, which is the same as 0-255 or 16-235, respectively). If using MadVR and Nvidia graphics card, in addition to what I just told you, you will also have to set the MadVR dynamic range as well.

Because of this, having patterns already checked is needed to make sure you don't miss set those other settings.

If you really want to go big, you can buy a pattern generator. The better ones will set you back $1000-2600, depending on mfrs., models, and features.
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post #2019 of 2031 Old 05-05-2019, 03:49 PM
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For most users, the i1Pro2 and the i1Display Pro are going to be the optimal choices.

This is a spectrophotometer that reads in 10nm wavelengths the color spectrum, but can be put in a higher detail mode which is around 3.5nm wavelengths. This will be fine for most users, but if you absolutely need more detail, you would need a CR-250 for about $6000 (IIRC), a Jeti for around $9000+, or even more expensive reference equipment. You can also pick up a used i1Pro 2 on ebay if needed.
Hi,
Would you be kind enough to elaborate on putting the iPro 2 into higher detail mode. I never knew that. I would love to try it out. Thanks.
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post #2020 of 2031 Old 05-05-2019, 04:36 PM
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Hi,
Would you be kind enough to elaborate on putting the iPro 2 into higher detail mode. I never knew that. I would love to try it out. Thanks.
It varies by program on how to do it. HCFR is nice and easy. When you get to the Argyll Sensor page before getting to doing the readings (where you can calibrate the meter, switch to ambient mode, change the observer type, or in the next tab do sensor matrix), you just need to check the "Use Hi-Res Mode (i1Pro & Colormunki Photo Only)" box.

Here is a bit of info from Argyll on hi-res mode: https://www.argyllcms.com/doc/i1proHiRes.html

I am unsure of where to set it in DisplayCal or in Calman. But, since I use HCFR using Argyll, it is fairly easy to setup.

Wish I could be of more help. I am sure others may be able to give more detail on this.
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@ajc9988 , Thanks a lot. Just the fact that it can be done helps me a lot. I will figure out. I use LightSpace. I will ask Ted or Steve. I am sure they must know. May be it already does it. You have already helped me. I had no idea it was a feature. I always read about the 10nm.
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post #2022 of 2031 Old 05-05-2019, 04:54 PM
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Originally Posted by Vishwa Somayaji View Post
@ajc9988 , Thanks a lot. Just the fact that it can be done helps me a lot. I will figure out. I use LightSpace. I will ask Ted or Steve. I am sure they must know. May be it already does it. You have already helped me. I had no idea it was a feature. I always read about the 10nm.
If you are just creating a CCSS for a colorimeter, you could theoretically create it in HCFR if they do not have the option in LightSpace (HCFR is a free program, as is ArgyllCMS, but I will mention it is always good to support the software developers through donations), then, if LightSpace has an option to import CCSS files, you can import it and then use LightSpace to do the calibration with your colorimeter. Just a thought.

Edit: And this note is attached as the summary of using Hi-Res mode for ArgyllCMS -
"In summary: the High Resolution mode is unquestionably useful for showing more spectral detail, and demonstrates promise of improved accuracy, but should probably not be used used for colorimetric measurement when the highest possible confidence is desired."
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Thanks. I will definitely check that out. Knowing it can be done was the key!
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post #2024 of 2031 Old 05-06-2019, 08:35 AM
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Thanks. I will definitely check that out. Knowing it can be done was the key!
Neither CalMAN nor LightSpace use the "high-res mode" with the I1Pro or Pro2, as far as I am aware. Their drivers are pretty much the standard X-Rite factory issue.
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Neither CalMAN nor LightSpace use the "high-res" mode with the I1Pro or Pro2, as far as I am aware. Their drivers are pretty much the standard X-Rite factory issue.
Thanks Rolls-Royce. In all the reviews and articles I read it was mentioned that the iPro 2 is a spectro with 10nm resolution. I am asking this here for my understanding. Is it internally only 10nm and HCFR is doing some kind of software enhancement or is there a better hardware than they publish inside iPro 2?
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Thanks Rolls-Royce. In all the reviews and articles I read it was mentioned that the iPro 2 is a spectro with 10nm resolution. I am asking this here for my understanding. Is it internally only 10nm and HCFR is doing some kind of software enhancement or is there a better hardware than they publish inside iPro 2?
@ConnecTEDDD is more up on this than I am (see his website at www.displaycalibrations.com for detailed info), but the sensors on the I1Pros are "binned" together to produce their readings. Perhaps you might be guided by the ArgyllCMS statement that "...the High-Resolution mode...should probably not be used for colorimetric measurement when the highest possible confidence is desired".

HCFR is using the Argyll driver, which is doing the software magic.
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post #2027 of 2031 Old 05-06-2019, 09:16 AM
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Thanks Rolls-Royce. In all the reviews and articles I read it was mentioned that the iPro 2 is a spectro with 10nm resolution. I am asking this here for my understanding. Is it internally only 10nm and HCFR is doing some kind of software enhancement or is there a better hardware than they publish inside iPro 2?
HCFR and DisplayCal are GUIs built atop the ArgyllCMS, at least in part. ArgyllCMS uses the higher resolution.

As described in the ArgyllCMS link:

"A spectrometer computes CIE tri-stimulus values by measuring spectral values and then weighing those values by the observer curves before summing the weigted values. The accuracy depends on the correct weighting being applied at each wavelength. If the color is composed of very narrow spectra peaks, as is sometimes the case for certain light sources and many display devices, then the exact positioning of one of the peaks on the observer curves may be influencial in the final color value, and too coarse a quanization of the spectral readings may lead to tri-stimulus errors. So in theory increasing the spectral reading resolution to 3.3 nm should lead to improved color accuracy with narrow spectra color sources."

"Another factor is that the calibration data for the instrument is only given at 10nm intervals. So to produce calibrated readings at 3.3nm intervals, it is necessary to up-sample the calibration data with sufficient accuracy. If the calibration data is sufficiently smooth (indicating that the underlying device characteristics are also smooth), or any slight inaccuracy will get calibrated out (which is typically the case for reflective measurements) then this may not be a limitation either. In the case of the i1pro2, which seems to have a diffraction grating/light sensor with a less smooth spectral efficiency curve than the Rev A - D models, the task of up-sampling the emissive calibration data with sufficient accuracy is more difficult."

https://www.argyllcms.com/doc/i1proHiRes.html

In other words, X-rite only calibrates and certifies the accuracy of the results at 10nm wavelength intervals. Because the data is "up-sample[d]," the question is whether there remains "sufficient accuracy" in the data between the 10nm wavelengths that the device is calibrated and certified to read correctly. This is why I put in the caveat on that page that using the Hi-Res mode"should probably not be used used for colorimetric measurement when the highest possible confidence is desired." Even though the experiment was shown to produce more accuracy in the limited testing with LCD displays, it showed outsized errors on CCRT displays. Since the device is not calibrated to accurately read at the 3.3nm intervals, the only measurements you can rely on with absolute confidence are at the 10nm wavelength intervals. That does NOT mean that it isn't receiving the 3.3nm wavelengths and reporting the data more accurately, it is that you cannot put absolute confidence in those readings because the device was never calibrated and certified to be accurate at those wavelengths.

So, it is a question of whether you want to trust the 3.3nm wavelength readings or not. In the limited testing, it did show, at many times, better tracking compared to the reference spectro. But that could vary by device and the display technology being profiled. As such, it very much is a "use at your own risk" sort of situation.

Also, for DisplayCal, I looked it up and when you set refresh or LCD for display type, it has two additional options: LCD (adaptive), and LCD (Hi-Res), or the combination of both. Adaptive allows the patch time to change, that way you can get better low luminance readings. Hi-Res uses the i1Pro 2's ability to do the 3.3nm readings, since it requires use of ArgyllCMS and drivers, it makes sense to implement Argyll's use of reading the 3.3nm for those that care to use it.

Does that help?
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@ajc9988 , Thanks and that indeed helps. I must, however, say upfront that 10nm is enough for what I do and am happy with iPro 2 as such. But, I always want my equipment(tool or pc or these spectros) to work at the best level they can and was intrigued that it indeed can work at a higher efficiency than the company certifies it.

There is some parallel here between what X-rite certifies the retail i1 Display pro ver B vs what they actually can measure(I think Tom Huffman showed that in his extensive study). Thanks for pointing it out. I will definitely see what I can do. Whether I am going to learn to use a new software just for that feature is a question I haven't answered yet to myself. But, if there is a way to import the calibration and use it in LightSpace, I will definitely try and compare the 10nm and 3.5nm versions of the calibration of my i1Display pro.

@Rolls-Royce , I will run it by Ted. May be he and Steve already know about it and decided not to use it for some good reason. Thanks for all the detailed explanations, guys. I really appreciate the opportunity to learn more things about the equipment I already own.
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duplicate.
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Quote:
Originally Posted by TomHuffman View Post
To calibrate the white balance:
  1. Aim the color analyzer at the display.
  2. Display a 80% video test pattern.
  3. Adjust the RGB Contrast controls until RGB is balanced at 100% or until you read x0.3127, y0.329.
  4. Display a 20% video test pattern and use the RGB Brightness controls to balance RGB at 100% or achieve x0.3127, y0.329.
  5. Repeat the last two steps as many times as necessary until both the 80% video and the 20% video patterns measure neutral gray. This may take several sets of measurements.
  6. Finally, take an entire series of white balance measurements--this is the grayscale--at 5% and then at 10% intervals up to 100%.
Sometimes you may find that even though 80% and 20% are a neutral gray, the mid range 40-60% is not. This means that your display won't track a good grayscale and you have to make some compromises. The general rule of thumb is to focus on getting the mid range to track neutral gray. Then get the low end right. Sacrifice accuracy at the top end if you have to.
This method has given me a lot of headaches on my TV. Using 30% and 80% or similar patterns.
I always ended up with an ok WB calibration after 10p WB calibration, except for below 20% and above 90%, which was way off.
My final approach, and this is probably because of my specific TV model, was to calibrate WB at a 10% and 109%, before calibrating 10p WB. It gave me by far the best grayscale overall, with all measurements being well below a DE2000 of one.
Just a FYI that the best approach might be dependent of the specific TV make & model.


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Setting Black Level (Brightness)
The typical method for setting black level is to use a pluge pattern that displays just above and just below black information against a black background. You set brightness so that the just-above-black is barely visible and the just-below-black is invisible. The closer the just-above and just-below information is to video black, the more precise the adjustment.

Here's another method that works well. Put up a 0% field on`1qqqqqqq the display. Turn brightness up several ticks. Now slowly start turning it down one click at a time. At some point you will find that lowering the brightness control further will not make the screen visibly darker. That is the correct setting. This can also be used to set black level for broadcast sources. If you have a DVR just record a fade-to-black sequence. Then play that back and pause it. Use this as your 0% test pattern.
There must be a better way, than to use this subjective approach. It counterfeits the argument about not to use subjective calibration of color & tint, as mentioned elsewhere.
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post #2031 of 2031 Old 06-03-2019, 03:04 AM - Thread Starter
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This method has given me a lot of headaches on my TV. Using 30% and 80% or similar patterns.
I always ended up with an ok WB calibration after 10p WB calibration, except for below 20% and above 90%, which was way off.
My final approach, and this is probably because of my specific TV model, was to calibrate WB at a 10% and 109%, before calibrating 10p WB. It gave me by far the best grayscale overall, with all measurements being well below a DE2000 of one.
Just a FYI that the best approach might be dependent of the specific TV make & model.



There must be a better way, than to use this subjective approach. It counterfeits the argument about not to use subjective calibration of color & tint, as mentioned elsewhere.
The human eye is very sensitive to even very small changes in luminance at low light levels. The subjective approach is quite accurate in a dark room.
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X Rite Eodis3 I1display Pro , X Rite Cmundis Colormunki Display , X Rite Eye One Display Lt , Calman 4 0 Calibration Software Home License , Aemc Ca813 Peak Function Lightmeter 200 000 Lux Range 0 01 Lux Resolution 3 Accuracy

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