Official JVC RS20 / HD750 Calibration and CMS thread (NEW FIRMWARE V1.1) - Page 4 - AVS Forum
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post #91 of 1634 Old 04-29-2009, 07:01 AM - Thread Starter
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Okay, I have done more tests and I am happy to report that if I calibrate with my cheap Display2, the tracking in linearity at 100% and 75% is excellent, including on green. I now have some doubts again about my i1 pro, as the display2 measures THX the way we know it is (pretty accurate from a gamut point of view) while the i1 pro repots some undersaturation in green.

I am doing a calibration with the i1 pro now (I put my old lamp back to take the new lamp out of the equation), and I will post detailed data from both calibrations then. Hopefully this will help someone with a 750/rs-20 and a reliable meter to tell me which one I should trust...
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post #92 of 1634 Old 04-29-2009, 07:02 AM
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Let's not let this devolve into a discussion about whether the Radiance is a good product (it is, in fact, a great one) and offers more than a CMS.

If the cost/benefit of using one with the RS20 was more in favor of the benefit side of the equation, it would be a no-brainer.

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post #93 of 1634 Old 04-29-2009, 07:28 AM
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Sounds good to me. The problem with many of these cheap probes is the need to calibrate them to the particular system being calibrated. Its not really a question of which probe of the cheap probes is better. The best results will be obtained using an expensive spectralradiometer for the whole sheebang. This is what the pros use and you just can`t obtain the same degree of acccuracy without one to at least correlate your cheap probe to an accurate reading. There are forums on calibration. But the use of expensive equipment is done for a reason. Cheap stuff can get you close but don1t assume that one cheap probe will give better results. It depens and there are many variables.

Manni. Call up someone with a good spectralradiometer and correlate your two probes. then you will get real close.

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post #94 of 1634 Old 04-29-2009, 08:01 AM - Thread Starter
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Quote:
Originally Posted by mark haflich View Post
Sounds good to me. The problem with many of these cheap probes is the need to calibrate them to the particular system being calibrated. Its not really a question of which probe of the cheap probes is better. The best results will be obtained using an expensive spectralradiometer for the whole sheebang. This is what the pros use and you just can`t obtain the same degree of acccuracy without one to at least correlate your cheap probe to an accurate reading. There are forums on calibration. But the use of expensive equipment is done for a reason. Cheap stuff can get you close but don1t assume that one cheap probe will give better results. It depens and there are many variables.

Manni. Call up someone with a good spectralradiometer and correlate your two probes. then you will get real close.
Thanks Mark, but from my point of view if an i1pro just out of the factory is not to be trusted, then I'm thinking of giving up calibration altogether!

Here is some data from my latest experiments.

1) As Tom remarked, green was too bright in my first attempt. It looks like this was the reason why there was a lack of linearity in my results. Pushing green too high seems to disturb the linearity.

2) I have calibrated with both the i1 pro and the display2 LT, and although they do not return similar results, they track the same between 75% and 100% as long as green's brightness is within reason. So my apologies for the first results: I repeat it for clarity: there is NO linearity problem with the new CMS. There are minor variations, but they are within what one could expect and are far beyond what I would personally expect from a consumer product.

3) I have taken my new lamp out and put back my old lamp, so the settings below may be better for some PJ.

4) There is a substantial difference between the measures taken by my i1pro and my d2. I attach a few files for those who are willing to look at the details, but would really appreciate if a 750/rs20 user with a meter they trust could try both settings below and tell me which one looks closer to rec709 on their PJ. I have my own opinion as to which one looks more "right", but I would rather not influence anyone.

I have calibrated with the i1pro in user1/custom1, and with the d2 in user2/custom2. I have set gamma to normal and color temp to the default 6500K in both to make sure I'm not introducing unknown variables to the equation.

Here are the settings (HSB):

user1/i1pro:
R=-4 -21 -2
Y=31 -44 40
G=-7 -42 34
C= -14 -49 40
B=30 0 -10
M=-7 0 -6

User2/d2:
R=-15 -16 -3
Y=7 -48 40
G=-36 -45 34
C= 13 -56 51
B=34 0 -7
M=-16 0 -4

As you can see, a pretty substantial difference!

The biggest being hue for cyan and green.

I have obviously not finetuned either of these calibrations as I need to find out first which meter is "right", if any.

Please Do not pay attention to the greyscale info if present in the attached files. I've only worked on the gamut.

 

2nd atttempt.zip 111.1708984375k . file
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post #95 of 1634 Old 04-29-2009, 08:15 AM - Thread Starter
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Last screenshots (i1Pro):
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post #96 of 1634 Old 04-29-2009, 08:34 AM - Thread Starter
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And just for fun, this is how the i1pro measures the d2 calibration:
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post #97 of 1634 Old 04-29-2009, 08:42 AM
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Ah, I've been keeping an eye out for the new firmware and now I see it's out with very positive impressions. I'll be updating my RS20 and recalibrating sometime in the next few days, after which I should be posting my new settings.
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post #98 of 1634 Old 04-29-2009, 08:44 AM
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Manni. You are missing the point. No because it is not designerd to do that. It has a certain degree of accuracy Iit can`t be trusted to be accurate over the entire necessary range. A certain points it will introduce significant errors but if you use an appropriate instrument (read expensive) to measure say the primaries accurately, one can offset the cheaper probes inaccuracies and get very very good results. The device is what it is. One doesn`t buy an expensive probe because the cheap probe deteriorates over time. Cheap probes can be recalibrated at the factory. Several are sensitive to varying temperatures and several are hydroscopic. You might get a quick idead by reading Tom Huffman`s calibration posts on the Planar SP-8150 thread

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post #99 of 1634 Old 04-29-2009, 08:52 AM
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Quote:
Originally Posted by Manni01 View Post

1) As Tom remarked, green was too bright in my first attempt. It looks like this was the reason why there was a lack of linearity in my results. Pushing green too high seems to disturb the linearity.

I must have missed Tom's comments. Can you repost them or provide a link to them? I'd like to see specifically what he was referring to.

Quote:


3) I have taken my new lamp out and put back my old lamp, so the settings below may be better for some PJ.

So it sounds like you have two variables that have changed simultaneously - the green brightness adjustment you have made AND going back to your old bulb. So can you be sure the green linearity was solved by Tom's recommendation and not the result of going back to the old bulb?

Quote:


As you can see, a pretty substantial difference! The biggest being hue for cyan and green.

If you have not yet flatted out your grayscale I recommend doing so at this time. It is the #1 reason IMO of any hue errors you are seeing.

Quote:


Please Do not pay attention to the greyscale info if present in the attached files. I've only worked on the gamut.

Ahh, ok I see you have not yet done the grayscale fully. This is like trying to scoop water out of a boat before plugging the hole. I'm all for obsessing about perfect color as you know, but to do so before getting the grayscale as flat as possible makes that almost impossible and will wind up driving you nuts! You don't have to mess with gamma for this, but grayscale, yes.
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post #100 of 1634 Old 04-29-2009, 09:02 AM
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Quote:
Originally Posted by Manni01 View Post

There is a substantial difference between the measures taken by my i1pro and my d2. I attach a few files for those who are willing to look at the details, but would really appreciate if a 750/rs20 user with a meter they trust could try both settings below and tell me which one looks closer to rec709 on their PJ. I have my own opinion as to which one looks more "right", but I would rather not influence anyone.

I would expect the biggest difference to be in green. What I would NOT expect is for the difference to be that large. This is a x0.014, y-0.027 discrepancy, which is huge. With a difference that large, you should be able to determine which is the correct reading with the naked eye.

There is something wrong with at least one of your meters. The problem could be in the D2.

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post #101 of 1634 Old 04-29-2009, 09:15 AM - Thread Starter
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Quote:
Originally Posted by lovingdvd View Post

I must have missed Tom's comments. Can you repost them or provide a link to them? I'd like to see specifically what he was referring to.



So it sounds like you have two variables that have changed simultaneously - the green brightness adjustment you have made AND going back to your old bulb. So can you be sure the green linearity was solved by Tom's recommendation and not the result of going back to the old bulb?



If you have not yet flatted out your grayscale I recommend doing so at this time. It is the #1 reason IMO of any hue errors you are seeing.



Ahh, ok I see you have not yet done the grayscale fully. This is like trying to scoop water out of a boat before plugging the hole. I'm all for obsessing about perfect color as you know, but to do so before getting the grayscale as flat as possible makes that almost impossible and will wind up driving you nuts! You don't have to mess with gamma for this, but grayscale, yes.

Re Tom's comment, you are right, he never said this. I have compared the new calibration with the i1pro and the old one, and green brightness was too high in the old one. Hence my deduction.

I went back to the old bulb without changing the settings, and the lack of linearity was still there (so putting the old bulb back didn't solve the problem).
It's only when I realised brightness for green was too high and adjusted it that the linearity problem disappeared.

Regarding the greyscale, I agree with you that this is the procedure that should be followed, but I'm not sure I understand in which way this is relevant here. There is no linearity problem with the new CMS, whether I calibrate to rec709 with the i1pro or the d2, as proved by the last files I've posted.

The only problem I have is I don't know which meter to trust, as they measure very different. But maybe I should take this discussion out of this thread, as it has nothing to do with the new CMS (apart from the fact that it would help me to provide better settings if I knew which meter to trust).

This is illustrated by the fact that the d2 measure the THX gamut as very close to rec709, while the i1pro measures it with green undersaturated.

Are you saying that doing the grescale will put the i1pro and the d2 on line? I don't understand why.

And which meter should I use to do the greyscale, if I don't find a way to decide which one should be trusted?

If there is no other way, I will follow Mark's suggestion to try to find someone with a reference meter, or maybe try another i1pro. I was sent a second one by mistake, I may open it and see if it measures the same.
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post #102 of 1634 Old 04-29-2009, 09:20 AM - Thread Starter
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Quote:
Originally Posted by TomHuffman View Post

I would expect the biggest difference to be in green. What I would NOT expect is for the difference to be that large. This is a x0.014, y-0.027 discrepancy, which is huge. With a difference that large, you should be able to determine which is the correct reading with the naked eye.

There is something wrong with at least one of your meters. The problem could be in the D2.

Thanks Tom, that's also what I think. The problem is that my eyes tell me the i1pro is correct (when do my greyscale with it, it's perfect, when I do it with the d2, it's slightly reddish). Unfortunately, the i1pro measures THX with a substantial green deficiency, while the d2 measures it bang on rec709. This is what throws me. I think we all agree that THX is rather close from a gamut POV, so I can't explain why the i1pro sees it so wrong.
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post #103 of 1634 Old 04-29-2009, 09:21 AM
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Quote:
Originally Posted by Manni01 View Post

Regarding the greyscale, I agree with you that this is the procedure that should be followed, but I'm not sure I understand in which way this is relevant here. There is no linearity problem with the new CMS, whether I calibrate to rec709 with the i1pro or the d2, as proved by the last files I've posted.

I'll defer to Tom and others for the formal explanation, but the bottom line is that if your grayscale is not flat, your colors will not be right, period (particularly hue).

Quote:


Are you saying that doing the grescale will put the i1pro and the d2 on line? I don't understand why.

No this has nothing to do with your meters but rather - a flat grayscale is mandatory for proper colors.

As for your differences in meters, that is odd. I highly recommend the combo of meters I use which is a Spyder 2 probe trained to an EyeOne Pro, and then taking measurements right out of the pj lens. Its been a winning combination for me for years.
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post #104 of 1634 Old 04-29-2009, 09:27 AM
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Originally Posted by Highlander_AVS View Post

The fact that Radiance used as processor, if needed, has other useful features it's out of doubts

Indeed, and specially after Greg measures report, CMS side you're speculating !

What do you think we need more than what Greg achieved ??

Sorry, not agree with Jim, but he wrote this last April 14th when no one known how worked the JVC Fix !!

Firstly... please stop calling me Greg. My name is Craig Rounds.

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post #105 of 1634 Old 04-29-2009, 09:30 AM
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Originally Posted by Mike_WI View Post

deandob -

1) I think your first question (bolded) is good.

2) I don't know that your second statement (bolded) is proven.
I am not a calibrator or very experienced, but to my naive eye, it doesn't seem like the CMS v1.1 has been proven to be perfect.
We have seen limited data from a few people. I certainly hope it is.
Also, the Lumagen devices may have some benefits besides CMS.

Here is the link to Craig Rounds (craigr, CIR Engineering) review of the JVC RS20 + Lumagen RadianceXE -- link.
Here is the AVS thread link where craigr posted the link and the commentary running after it -- link.

I look forward to peoples opinions and emerging data on this (especially since I have a RadianceXE and a calibration pending...)


Mike

Secondly, I will be calibrating Mike_WI 's RS20 on the 16th. I will collect and post data for the new firmware CMS on the RS20. I use a PR650 so my numbers will be accurate. Mike has already purchased an Lumagen Radiance XE from me and we will be installing that and using it with the RS20.

What I expect to do in terms of the CMS is first test the new RS20 alone. If the results are good I will not use the CMS in the Radiance XE. If the RS20 still tracks in a non-linear way with respect to xyY I will most likely disable the CMS and just use the Radiance CMS again. The RS20 performed pretty well with the CMS in the Radiance before and I doubt that will change with the new FW.

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post #106 of 1634 Old 04-29-2009, 09:31 AM - Thread Starter
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Quote:
Originally Posted by lovingdvd View Post

I'll defer to Tom and others for the formal explanation, but the bottom line is that if your grayscale is not flat, your colors will not be right, period (particularly hue).



No this has nothing to do with your meters but rather - a flat grayscale is mandatory for proper colors.

As for your differences in meters, that is odd. I highly recommend the combo of meters I use which is a Spyder 2 probe trained to an EyeOne Pro, and then taking measurements right out of the pj lens. Its been a winning combination for me for years.

Thanks LovingDVD, but the difference in meters is the only thing we are still discussing. I have used the d2 trained with the i1pro, and it's provided a more more precise and repeatable way to do work on the greyscale. It's just that calibrating after installing the new firmware threw that question about green variation and I'd like to get to the bottom of it.

I'm going to open a new thread if I don't find a way to solve this as this is distracting regarding the new CMS, which performs flawlessly as far as I can see.

I don't want my meter problems to take anything away from JVC's extraordinary achievement.

This new firmware rocks (and at least one of my meters suck$).
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post #107 of 1634 Old 04-29-2009, 09:32 AM
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Thirdly, I am sorry that I have not been around more after writing my original white paper on the RS20 and RS20 + Radiance combo. I have been swamped with actual calibration work and have not had time to post to the forums much this year. I am glad to have lots of work but sad that I don't have time to participate in discussions

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post #108 of 1634 Old 04-29-2009, 09:32 AM - Thread Starter
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Quote:
Originally Posted by CIR-Engineering View Post

Secondly, I will be calibrating Mike_WI 's RS20 on the 16th. I will collect and post data for the new firmware CMS on the RS20. I use a PR650 so my numbers will be accurate. Mike has already purchased an Lumagen Radiance XE from me and we will be installing that and using it with the RS20.

What I expect to do in terms of the CMS is first test the new RS20 alone. If the results are good I will not use the CMS in the Radiance XE. If the RS20 still tracks in a non-linear way with respect to xyY I will most likely disable the CMS and just use the Radiance CMS again. The RS20 performed pretty well with the CMS in the Radiance before and I doubt that will change with the new FW.

craigr

Craig, the new CMS tracks in a perfectly linear way. I am sorry my meter problems raised a question about this, but as far as I can see, there is NO linearity issue with the new CMS. Full stop.
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post #109 of 1634 Old 04-29-2009, 09:34 AM
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Quote:
Originally Posted by Manni01 View Post

Thanks LovingDVD, but the difference in meters is the only thing we are still discussing. I have used the d2 trained with the i1pro, and it's provided a more more precise and repeatable way to do work on the greyscale. It's just that calibrating after installing the new firmware threw that question about green variation and I'd like to get to the bottom of it.

I'm going to open a new thread if I don't find a way to solve this as this is distracting regarding the new CMS, which performs flawlessly as far as I can see.

I don't want my meter problems to take anything away from JVC's extraordinary achievement.

This new firmware rocks (and at least one of my meters suck$).

A lot of meters can measure gray scale well, but many of the same meters struggle with primary and secondary colors. As you have observed, green is usually the most inconsistent across different meters. The only meter I trust for green is my PR650. I also have an EyeOne Beamer and it measures green totally different than the PR650... and I consider the EyeOne to be one of the most accurate inexpensive meters.

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post #110 of 1634 Old 04-29-2009, 09:35 AM
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Quote:
Originally Posted by Manni01 View Post

Craig, the new CMS tracks in a perfectly linear way. I am sorry my meter problems raised a question about this, but as far as I can see, there is NO linearity issue with the new CMS. Full stop.

SWEET I can't wait to see it!!!

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post #111 of 1634 Old 04-29-2009, 09:35 AM
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Originally Posted by Manni01 View Post

Thanks LovingDVD, but the difference in meters is the only thing we are still discussing.

As posted above my comment about fixing your grayscale was specifically directed at your comment "As you can see, a pretty substantial difference! The biggest being hue for cyan and green."
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post #112 of 1634 Old 04-29-2009, 09:42 AM - Thread Starter
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Originally Posted by lovingdvd View Post

As posted above my comment about fixing your grayscale was specifically directed at your comment "As you can see, a pretty substantial difference! The biggest being hue for cyan and green."

Yes, but how do you want me to do the greyscale if I don't know which meter to use?

I could do two greyscales, one with each meter, they would both measure perfectly with each meter.

But they would both be different.

So which one should I use to work on the gamut?

This is why I reverted to the 6500K setting, just to take greyscale out of the equation.

As I said, my eyes tell me the i1pro is more "right" than the d2. If it was showing the THX gamut on rec709, we wouldn't even be discussing this. What I find puzzling is the fact that it's the opposite, the D2 shows THX on rec 709, and the i1pro shows it substantially undersaturated.
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post #113 of 1634 Old 04-29-2009, 09:49 AM
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Quote:
Originally Posted by Manni01 View Post

Yes, but how do you want me to do the greyscale if I don't know which meter to use?

I could do two greyscales, one with each meter, they would both measure perfectly with each meter.

But they would both be different.

So which one should I use to work on the gamut?

This is why I reverted to the 6500K setting, just to take greyscale out of the equation.

As I said, my eyes tell me the i1pro is more "right" than the d2. If it was showing the THX gamut on rec709, we wouldn't even be discussing this. What I find puzzling is the fact that it's the opposite, the D2 shows THX on rec 709, and the i1pro shows it substantially undersaturated.

Good point, I see your dilemma. Which meter did you do all your original CMS work on (pre-firmware fix)? Did you suspect any issues with meter accuracy back then?
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post #114 of 1634 Old 04-29-2009, 09:51 AM
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Originally Posted by Manni01 View Post

Okay, I have done more tests and I am happy to report that if I calibrate with my cheap Display2, the tracking in linearity at 100% and 75% is excellent, including on green. I now have some doubts again about my i1 pro, as the display2 measures THX the way we know it is (pretty accurate from a gamut point of view) while the i1 pro repots some undersaturation in green.

I am doing a calibration with the i1 pro now (I put my old lamp back to take the new lamp out of the equation), and I will post detailed data from both calibrations then. Hopefully this will help someone with a 750/rs-20 and a reliable meter to tell me which one I should trust...

Hi Manni. With a brand new Pro I measured undersaturation of all colours but significantly green with the standard THX preset which sounds consistent with what you are seeing. I know what you are saying though as I have also read conflicting reports of others measuring the THX preset being spot. To me this also raised the question of accuracy of my own Pro.

I think it unlikely that both our Pro's are 'off'. I guess we either need to send them back to be tested or get the measurements validated by someone with another probe taking simultaneous readings.

By eye the THX preset looks undersaturated to me but when calibrating to spot on Rec 709 with my Radiance skin tones look mildly oversaturated.
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post #115 of 1634 Old 04-29-2009, 09:57 AM - Thread Starter
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Originally Posted by 008 View Post

Hi Manni. With a brand new Pro I measured undersaturation of all colours but significantly green with the standard THX preset which sounds consistent with what you are seeing. I know what you are saying though as I have also read conflicting reports of others measuring the THX preset being spot. To me this also raised the question of accuracy of my own Pro.

I think it unlikely that both our Pro's are 'off'. I guess we either need to send them back to be tested or get the measurements validated by someone with another probe taking simultaneous readings.

By eye the THX preset looks undersaturated to me but when calibrating to spot on Rec 709 with my Radiance skin tones look mildly oversaturated.

Thanks 008, this is good to hear.

To me, the i1pro does look more right than the d2, especially when looking at a greyscale done by each separately (steps of grey with the i1pro, slight red tint with the d2).

I'm going to assume the i1pro is more right, that THX is off (as I also felt THX was undersaturated), work on the greyscale like I used to with the D2 trained on the i1Pro, and I'll report with a final calibration.

Hopefully this will put the matter to rest!
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post #116 of 1634 Old 04-29-2009, 10:08 AM
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Originally Posted by Manni01 View Post

I'll do this when I try calibrating at 75% and will post results in the HCFR files.

Any chance to run the saturation windows? Your calibration looks fantastic so far at 100% saturation (and 100% or 75% stimulus), but am wondering about how well the RS-20 reproduces the inner part of the color gamut. Thanks.

Dan
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post #117 of 1634 Old 04-29-2009, 10:47 AM
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Originally Posted by CIR-Engineering View Post

Firstly... please stop calling me Greg. My name is Craig Rounds.

craigr

I would bet that he was referring to Greg Rogers and the excellent results he achieved with the JVC CMS alone earlier in the thread. Greg posted his measured results and has shown that the CMS does track linearly and appears to work as promised.

Absence of evidence is not evidence of absence

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post #118 of 1634 Old 04-29-2009, 10:59 AM
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Originally Posted by CIR-Engineering View Post

Firstly... please stop calling me Greg. My name is Craig Rounds.

craigr

Sorry, but, First I was not refering at You !
I was talking about Greg Rogers and his measures posted here:
http://www.avsforum.com/avs-vb/showp...7&postcount=65
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post #119 of 1634 Old 04-29-2009, 11:18 AM
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Originally Posted by mrlittlejeans View Post

I would bet that he was referring to Greg Rogers and the excellent results he achieved with the JVC CMS alone earlier in the thread. Greg posted his measured results and has shown that the CMS does track linearly and appears to work as promised.

Shure !
Thanks
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post #120 of 1634 Old 04-29-2009, 11:40 AM
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Originally Posted by Manni01 View Post

Yes, but how do you want me to do the greyscale if I don't know which meter to use?

I could do two greyscales, one with each meter, they would both measure perfectly with each meter.

But they would both be different.

So which one should I use to work on the gamut?

This is why I reverted to the 6500K setting, just to take greyscale out of the equation.

As I said, my eyes tell me the i1pro is more "right" than the d2. If it was showing the THX gamut on rec709, we wouldn't even be discussing this. What I find puzzling is the fact that it's the opposite, the D2 shows THX on rec 709, and the i1pro shows it substantially undersaturated.

As Craig and others mentioned before, many of the non-expensive meters can measure gray scale with some accuracy but really go off when trying to measure primaries. If you are getting two different grayscales, you need to find out which is more correct and stop using the other......

Glen Carter
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www.ISFHT.com
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