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The Official ChromaPure thread - Page 128

post #3811 of 5345
Quote:
Originally Posted by Toe View Post

Thanks. Measuring 100% white should be reliable, but will measuring black on my RS45 at the screen be doable? I thought I read that readings down that low are not reliable, or do I have this wrong?
The documentation in CP is really pretty good, so I encourage everyone to take advantage of it. Quoting from the Help file (Using Auto-Calibrate, BT.1886 Gamma) "If you have a JVC projector whose black level you cannot read, then simply measure the contrast ratio by pointing the probe at the lens (using a diffuser). Once you have the ratio between black and white, just take a reading from the screen for 100% white, then you can calculate the black level from this."
post #3812 of 5345
Anyone care to comment on the post calibration color gamut shown here jan 22 post-cal color gamut1.jpg 74k .jpg file or the ACM Chromacity garph shown here ACM Chormacity.jpg 21k .jpg file

I think they are looking like they are supposed to look. Some errors on blue and yellow but I think that stems from teh fact I can't back any more red out of my Blue.

How about the Blue luminance is that showing a high error I need to work on?
post #3813 of 5345
Your dE's are lower than 1, all lower than humanly visible. Even if you could get them lower, you wouldn't be able to see a difference. The only thing you could do is see what makes the colors track better, using 75 or 100% patterns.
post #3814 of 5345
Quote:
Originally Posted by rocketman9 View Post

So this might be a dumb question, but from my Color Managment file attached above is it fair to say that looking at Green, I need to go into Custom Color Green and DROP the green setting and increase both Red and Blue? It just seems odd to add red and blue to my green to make it right....

Not a techy person but I think the maths of the YCbCr part of Rec 709 means that green is measured after taking the blue (Cb) and red (Cr) away from the Y (Luminance), so if you adjust green you effectively change the gamma as well.

At least that's what happens if I change green.

Others may perhaps correct my understanding of the process.
post #3815 of 5345
Quote:
Originally Posted by rocketman9 View Post

So this might be a dumb question, but from my Color Managment file attached above is it fair to say that looking at Green, I need to go into Custom Color Green and DROP the green setting and increase both Red and Blue? It just seems odd to add red and blue to my green to make it right....
Green is oversaturated with too much luminance. To desaturate, you add equal amounts of the other two primaries. To low luminance you lower the amount of the same color (green).
post #3816 of 5345
Quote:
Originally Posted by TomHuffman View Post

The documentation in CP is really pretty good, so I encourage everyone to take advantage of it. Quoting from the Help file (Using Auto-Calibrate, BT.1886 Gamma) "If you have a JVC projector whose black level you cannot read, then simply measure the contrast ratio by pointing the probe at the lens (using a diffuser). Once you have the ratio between black and white, just take a reading from the screen for 100% white, then you can calculate the black level from this."

Good deal. Thanks again.
post #3817 of 5345
Quote:
Originally Posted by rocketman9 View Post

Anyone care to comment on the post calibration color gamut shown here jan 22 post-cal color gamut1.jpg 74k .jpg file or the ACM Chromacity garph shown here ACM Chormacity.jpg 21k .jpg file

I think they are looking like they are supposed to look. Some errors on blue and yellow but I think that stems from teh fact I can't back any more red out of my Blue.

How about the Blue luminance is that showing a high error I need to work on?

How about the Luminance chart in this Quick Report? It shows a 5.5% error (I think) for blue. Is this something that needs adjustment? The dE on blue isn't high....
Edited by rocketman9 - 1/23/13 at 9:52pm
post #3818 of 5345
Quote:
Originally Posted by TomHuffman View Post

The documentation in CP is really pretty good, so I encourage everyone to take advantage of it. Quoting from the Help file (Using Auto-Calibrate, BT.1886 Gamma) "If you have a JVC projector whose black level you cannot read, then simply measure the contrast ratio by pointing the probe at the lens (using a diffuser). Once you have the ratio between black and white, just take a reading from the screen for 100% white, then you can calculate the black level from this."

I should have read it before. Really good information!
post #3819 of 5345
Hello. What is one of the best ways to go about doing gamma. Last night I did multiple adjustments to the gamma my target is 2.22. Everytime I noticed when using the Gamma module with the 100% white value in place and setting my gamma at 2.22 during the adjustments that when I go to take a post greyscale run my gamma in the 90% white drops to 2.16. 80% and 70% drops as well. What I am trying to get at is what is the best approach in calibrating the gamma when you adjust one interval but then it could effect another. Say adjust 90 and then 80 then check 90? any tips to get it more linear and near target specially at 70, 80, 90 % white.
post #3820 of 5345
Quote:
Originally Posted by hungro View Post

Hello. What is one of the best ways to go about doing gamma. Last night I did multiple adjustments to the gamma my target is 2.22. Everytime I noticed when using the Gamma module with the 100% white value in place and setting my gamma at 2.22 during the adjustments that when I go to take a post greyscale run my gamma in the 90% white drops to 2.16. 80% and 70% drops as well. What I am trying to get at is what is the best approach in calibrating the gamma when you adjust one interval but then it could effect another. Say adjust 90 and then 80 then check 90? any tips to get it more linear and near target specially at 70, 80, 90 % white.

What display? Assuming 10 point grayscale, try adjusting 90% with the 80% control, 80% with the 70% control, etc.
post #3821 of 5345
Quote:
Originally Posted by buzzard767 View Post

What display? Assuming 10 point grayscale, try adjusting 90% with the 80% control, 80% with the 70% control, etc.

It's a Samsung plasma. PN51D6500.
post #3822 of 5345
You are apparently doing a gamma run and then measuring 90% while you adjust with the 90% controls. It probably changes 100% so when you reset and do another run 100% now has a different luminance and 90% is now incorrect.

1 .Measure 90%
2. Adjust with the 80% controls and see if that helps.
post #3823 of 5345
Quote:
Originally Posted by buzzard767 View Post

You are apparently doing a gamma run and then measuring 90% while you adjust with the 90% controls. It probably changes 100% so when you reset and do another run 100% now has a different luminance and 90% is now incorrect.

1 .Measure 90%
2. Adjust with the 80% controls and see if that helps.

You mean after first adjusting 90% as good as possible with the 90% controls?

And when you move on to measuring and adjusting 80%, won't the required changes to the 80% and 70% controls change 90% measurement? And on, and on .... like Dominoes .... Won't subsequent adjustments all the way down ripple back all the way to 100%?
post #3824 of 5345
Quote:
Originally Posted by kjgarrison View Post

You mean after first adjusting 90% as good as possible with the 90% controls?

And when you move on to measuring and adjusting 80%, won't the required changes to the 80% and 70% controls change 90% measurement? And on, and on .... like Dominoes .... Won't subsequent adjustments all the way down ripple back all the way to 100%?
The thing folks need to realize about 10 point (or 20 point) adjustments is:
  • Often (usually) the center point of a given adjustment is NOT at the stated point (a "80%" adjustment) may well be at an different point (like 89%).
  • The "width" of the adjustment may be relatively wide - so there is interaction with adjacent points.
post #3825 of 5345
Quote:
Originally Posted by davehancock View Post

The thing folks need to realize about 10 point (or 20 point) adjustments is:
  • Often (usually) the center point of a given adjustment is NOT at the stated point (a "80%" adjustment) may well be at an different point (like 89%).
  • The "width" of the adjustment may be relatively wide - so there is interaction with adjacent points.

I noticed it also. After 10pt adjustment, simply take 5% readings. There can be huge differencies. Advice is, make small steps and always check previous interval.
post #3826 of 5345
Quote:
Originally Posted by kjgarrison View Post

You mean after first adjusting 90% as good as possible with the 90% controls?

And when you move on to measuring and adjusting 80%, won't the required changes to the 80% and 70% controls change 90% measurement? And on, and on .... like Dominoes .... Won't subsequent adjustments all the way down ripple back all the way to 100%?

No. First set 100%. Then measure 90% but try adjusting 90% with the 80% controls. Every TV is different so you have to see what works and what doesn't - part of why some calibrations can be very time consuming. smile.gif

The "domino theory" is part of what convinced me to be a Marine in Viet Nam. Seriously, on nearly every display I've seen, once you get 100 - 80% where you want them the rest of the luminance points are not nearly as disruptive.
post #3827 of 5345
Remember too that 80-90-100% relative gammas are very sensitive to probe and display repeatability (ratios of small numbers). A 1% change in either 90% luminance relative to 100% or vice-versa will shift gamma by 0.1 In reality the gamma values at these levels can be pretty unstable and are considerably less important than the lower stimulus values.
post #3828 of 5345
Zoyd, if I read you right the real key to calibrating grayscale is to get 10-20-30% right? I know that is putting words in your mouth so I am not saying that you said that, I am asking "Did I interpret what you said correctly?"

If that is the case, how can we get that right, given that many meters don't operate as accurately at low stimulus levels (I think)?
post #3829 of 5345
Quote:
Originally Posted by rocketman9 View Post

Zoyd, if I read you right the real key to calibrating grayscale is to get 10-20-30% right? I know that is putting words in your mouth so I am not saying that you said that, I am asking "Did I interpret what you said correctly?"

If that is the case, how can we get that right, given that many meters don't operate as accurately at low stimulus levels (I think)?

Not exactly, I was talking about gamma calibration (Y) which all meters can do reliably down to 10%. The point being that for gamma the upper end, say 80% and 90% is pretty irrelevant perceptually and can also be hard to pin down as people have pointed out. It doesn't matter if the 90% level is 2.2 or 2.3. On the other hand greyscale is very important to nail down at every level your meter is capable of.
post #3830 of 5345
Is there a trial version of Chromapure available? I am trying to decide if I want to go HCFR, Calman or Chromapure.

Any comments on the relative strengths and weaknesses? What made all you Chromapure users pick it?
post #3831 of 5345
Hello,

I have a problem with my i1 Display PRO meter. It is very hard (and long) to read high IRE like 80%.
Chromapure "doesn't answer" for a long time, then gives me a wrong reading. I must redo the measure several times.

I have my meter connected to my PC via another USB cable.
I'm using a French version of Windows 7, does it matter too ?

Thanks for the help.
Remi.
post #3832 of 5345
Novice calibrator here -- picked up a CP Standard/Display 3 Pro package from Tom recently and spent a few hours last night making several rounds of adjustments on my Panasonic 60ST50. Not nearly as intimidating as I first thought it would be. I'd be interested in any opinions of my inaugural results.





While the overall light output is on the low side (~22.5 fL), our viewing area is typically dimly lit, and the image really pops.

Any suggestions for subsequent button-pressing sessions? (And yes, there will be more -- this is nearly as much fun as watching a good blu-ray!)
post #3833 of 5345
Quote:
Originally Posted by sobi View Post

Novice calibrator here -- picked up a CP Standard/Display 3 Pro package from Tom recently and spent a few hours last night making several rounds of adjustments on my Panasonic 60ST50. Not nearly as intimidating as I first thought it would be. I'd be interested in any opinions of my inaugural results.





While the overall light output is on the low side (~22.5 fL), our viewing area is typically dimly lit, and the image really pops.

Any suggestions for subsequent button-pressing sessions? (And yes, there will be more -- this is nearly as much fun as watching a good blu-ray!)
You should be getting more light than 22.5 ft-L. What Picture mode are you in? Try Custom. Everything else looks good.
post #3834 of 5345
Quote:
Originally Posted by mlg33 View Post

Hello,

I have a problem with my i1 Display PRO meter. It is very hard (and long) to read high IRE like 80%.
Chromapure "doesn't answer" for a long time, then gives me a wrong reading. I must redo the measure several times.

I have my meter connected to my PC via another USB cable.
I'm using a French version of Windows 7, does it matter too ?

Thanks for the help.
Remi.
By "another USB cable" do you mean a USB extender? This is probably too long. It shouldn't be over 3 meters.
post #3835 of 5345
Quote:
Originally Posted by marcojames View Post

Is there a trial version of Chromapure available? I am trying to decide if I want to go HCFR, Calman or Chromapure.

Any comments on the relative strengths and weaknesses? What made all you Chromapure users pick it?
Contact Customer Support and we can give you a copy with a simulated meter. You can also view the Demos on our web page.
post #3836 of 5345
Yes. And then Press OK several times as prompted.
post #3837 of 5345
Quote:
Originally Posted by TomHuffman View Post

You should be getting more light than 22.5 ft-L. What Picture mode are you in? Try Custom. Everything else looks good.

I am in Custom -- it's the only mode on this model that offers access to its "Pro" settings' two-point grayscale adjustment. I'll crank up the output to 30+ fL next time I play with it.

I know there are more granular adjustments in the service menu -- anyone here have any experience working in the SM on recent Panasonic plasmas? I'm wondering if it might be worth trying to improve those primary and secondary numbers, or if I should leave well enough alone.
post #3838 of 5345
Quote:
Originally Posted by TomHuffman View Post

Contact Customer Support and we can give you a copy with a simulated meter. You can also view the Demos on our web page.
Thanks. Yes I'm using a 3 meter USB extension.
May that's what cause the problem.

And sorry to ask it again :
But some users are using Small APL patterns to calibrate their Panasonic Plasma 2012 (ST50 in my case).
Do you still advise the Windows patterns only ?

Thank you.
post #3839 of 5345
Quote:
Originally Posted by mlg33 View Post

Thanks. Yes I'm using a 3 meter USB extension.
May that's what cause the problem.

And sorry to ask it again :
But some users are using Small APL patterns to calibrate their Panasonic Plasma 2012 (ST50 in my case).
Do you still advise the Windows patterns only ?

Thank you.
Small windows are fine. What is not fine is full fields.
post #3840 of 5345
I also use a usb extension, but with an amplifier build into the plug thats on the cord. I have no problems at all. Make sure your wire is not curled up in a bundle though, the cord has to be free. I have had malfunctions on other equipment with that (scanner)
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