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post #6421 of 7446 Old 04-07-2015, 07:05 AM
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Tom, I've seen measurements here showing low delta errors and almost perfect grayscale charts, but not so great gamma, and sometimes the opposite. While each is vital, which do you think is more important to get right?
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post #6422 of 7446 Old 04-07-2015, 11:35 AM
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Originally Posted by Pres2play View Post
Tom, I've seen measurements here showing low delta errors and almost perfect grayscale charts, but not so great gamma, and sometimes the opposite. While each is vital, which do you think is more important to get right?
White balance errors are more serious than gamma. Even relatively small white balance errors can be easily visible. Small deviations in gamma are not nearly as important.
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post #6423 of 7446 Old 04-07-2015, 12:38 PM
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Really didn't know that. Wish I had asked sooner, I've been focusing on perfect gamma all this time.
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post #6424 of 7446 Old 04-07-2015, 02:46 PM
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Originally Posted by Pres2play View Post
Really didn't know that. Wish I had asked sooner, I've been focusing on perfect gamma all this time.
EBU Tech 3320v3 - recommends gamma +/- .1 for CRT monitors. Better said, 2.3 - 2.5, and, they now endorse BT.1886. Bottom line, relax and concentrate on getting color out of gray.
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post #6425 of 7446 Old 04-07-2015, 04:08 PM
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Originally Posted by buzzard767 View Post
EBU Tech 3320v3 - recommends gamma +/- .1 for CRT monitors. Better said, 2.3 - 2.5, and, they now endorse BT.1886. Bottom line, relax and concentrate on getting color out of gray.

Funny you mention color. The more I strive to get the gamma to flatline at 2.22, the more de-saturated my colors become.


However, I only notice this on the gamut chart, and not with real content.
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post #6426 of 7446 Old 04-07-2015, 06:27 PM
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I've always wanted a test pattern that is a continuous gray ramp with tick marks at the 5% and 10% intervals. I've seen ramps with 16 and 235 marked, but never one with any values between. Using the continuous ramp I can see color variations that are between the control points I calibrate, but it's hard to tell exactly where they are to determine where a tweak might help. Has anyone seen anything like that?
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post #6427 of 7446 Old 04-08-2015, 12:27 AM
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Originally Posted by rmongiovi View Post
I've always wanted a test pattern that is a continuous gray ramp with tick marks at the 5% and 10% intervals. I've seen ramps with 16 and 235 marked, but never one with any values between. Using the continuous ramp I can see color variations that are between the control points I calibrate, but it's hard to tell exactly where they are to determine where a tweak might help. Has anyone seen anything like that?
Something like this?

http://www.chromapure.com/increments.png

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post #6428 of 7446 Old 04-08-2015, 06:45 AM
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Originally Posted by TomHuffman View Post
What would be really cool would be a ramp at the top/bottom with a marker where you are and a test square in the middle for your meter to measure so you can get feedback from the meter while also seeing the impact on the ramp...
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post #6429 of 7446 Old 04-08-2015, 07:16 AM
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That's pretty much exactly what I'm looking for Tom. Is that on your disk?
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post #6430 of 7446 Old 04-08-2015, 09:14 AM
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Originally Posted by Pres2play View Post
Funny you mention color. The more I strive to get the gamma to flatline at 2.22, the more de-saturated my colors become.

I take that back, adjusting WB I see no affect on gamut points.
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post #6431 of 7446 Old 04-08-2015, 12:03 PM
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Originally Posted by rmongiovi View Post
That's pretty much exactly what I'm looking for Tom. Is that on your disk?
No, it is just something I made up on the spur of the moment. I can include it in the built-in test patterns for v 3.

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post #6432 of 7446 Old 04-08-2015, 01:55 PM
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Thanks, but don't do it just for me. I would want it on a disk or as a pattern on my Lumagen.
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post #6433 of 7446 Old 04-08-2015, 02:12 PM
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Quote:
Originally Posted by rmongiovi View Post
Thanks, but don't do it just for me. I would want it on a disk or as a pattern on my Lumagen.
I'd certainly like to see that in V3.0. Perhaps there should be 2 sets: Full digital range (with markings showing bits) and the video range one.

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post #6434 of 7446 Old 04-09-2015, 07:32 AM
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Quote:
Originally Posted by Pres2play View Post
Funny you mention color. The more I strive to get the gamma to flatline at 2.22, the more de-saturated my colors become.


However, I only notice this on the gamut chart, and not with real content.
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I take that back, adjusting WB I see no affect on gamut points.
Gamma affects saturation, hue, and brightness -- for example, saturation increases as gamma is raised and it's one of the reasons some folks prefer a higher gamma.

Greg Rogers explains it very well in this post: https://www.avsforum.com/forum/24-dig...l#post20927047

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post #6435 of 7446 Old 04-09-2015, 04:03 PM
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Geof, thanks for posting that link. Is that a typo in example 2 ?


...2) Color (a yellow complementary color with 100% gamut saturation)
R' G' B'
0.75 0.75 0
R G B (2.2 gamma display)
0.53 0.53 0
R G B (2.4 gamma display)
0.50 0.50 0

Again there is a brightness change but nothing else because the proportions of red and green don't change...

Last edited by Pres2play; 04-09-2015 at 04:33 PM.
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post #6436 of 7446 Old 04-09-2015, 04:23 PM
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Here's what I mean. To fix luminance for red I lowered red component; to adjust blue, I lowered blue component. Red and blue color points are now farther from target in post-cal.

pre-cal gamut


post-cal gamut

Last edited by Pres2play; 06-14-2017 at 08:05 PM.
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post #6437 of 7446 Old 04-09-2015, 05:03 PM
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^^^Wrong images. The above involved changes to luminance, not gamma. I'll use higher gamma to get neutral grays if I must, and report back.
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post #6438 of 7446 Old 04-10-2015, 08:10 AM
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Quote:
Originally Posted by Pres2play View Post
Geof, thanks for posting that link. Is that a typo in example 2 ?


...2) Color (a yellow complementary color with 100% gamut saturation)
R' G' B'
0.75 0.75 0
R G B (2.2 gamma display)
0.53 0.53 0
R G B (2.4 gamma display)
0.50 0.50 0

Again there is a brightness change but nothing else because the proportions of red and green don't change...
I don't see any typo's....

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post #6439 of 7446 Old 04-10-2015, 08:46 AM
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Apologies, I misread the figures.



Is 2.4 gamma recommended for the entire grayscale, or just at various intensity levels?
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post #6440 of 7446 Old 04-10-2015, 09:08 AM
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Apologies, I misread the figures.



Is 2.4 gamma recommended for the entire grayscale, or just at various intensity levels?
Tom and others are more qualified to answer this but I think generally one uses the same gamma targets for all stimulus levels except when calibrating to BT1886. That said, at times I've calibrated my projector to 2.3 where I gradually lower gamma at 20% and below to help mitigate black crush. I don't think there is any right or wrong depending on your tastes.

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post #6441 of 7446 Old 04-10-2015, 09:12 AM
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Originally Posted by geof View Post
tom and others are more qualified to answer this but i think generally one uses the same gamma targets for all stimulus levels except when calibrating to bt1886. That said, at times i've calibrated my projector to 2.3 where i gradually lower gamma at 20% and below to help mitigate black crush. i don't think there is any right or wrong depending on your tastes.
bt1886

Loving D65
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post #6442 of 7446 Old 04-10-2015, 07:33 PM
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Quote:
Originally Posted by Geof View Post
Tom and others are more qualified to answer this but I think generally one uses the same gamma targets for all stimulus levels except when calibrating to BT1886. That said, at times I've calibrated my projector to 2.3 where I gradually lower gamma at 20% and below to help mitigate black crush. I don't think there is any right or wrong depending on your tastes.

Thanks, Geof. I'll experiment more this weekend using the information you linked. I'm very satisfied with the calibration I have now, btw. Just want to increase my knowledge base and have some fun messing with this stuff.
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post #6443 of 7446 Old 04-11-2015, 07:15 AM
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I would like to see this test pattern included also.
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post #6444 of 7446 Old 04-14-2015, 08:30 PM
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I want to run the color checker with chromapure, but I do not want to use the built in chart generator with chromapure.
Does anyone know where I can obtain that chart to burn to a disc to play on a bluray or DVD player?
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post #6445 of 7446 Old 04-14-2015, 11:59 PM
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Using 2.3 gamma was enough to get the color points back on target. Wish I had lowered gamma starting around 40 IRE, though, instead of 20 IRE, for better shadows. I'll do that next time.







Last edited by Pres2play; 06-14-2017 at 08:05 PM.
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post #6446 of 7446 Old 04-15-2015, 12:24 AM
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I want to run the color checker with chromapure, but I do not want to use the built in chart generator with chromapure.
Does anyone know where I can obtain that chart to burn to a disc to play on a bluray or DVD player?
ConecTed's disc has colourchecker patterns i believe
http://www.displaycalibrations.com/r...ad_no_ads.html

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post #6447 of 7446 Old 04-15-2015, 12:25 AM
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I want to run the color checker with chromapure, but I do not want to use the built in chart generator with chromapure.
Does anyone know where I can obtain that chart to burn to a disc to play on a bluray or DVD player?
Our calibration Blu-ray has this. So does Masicor's disc and I believe Ted's disc. Other discs have ColorChecker patterns, though the precise RGB values may be slightly different.
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post #6448 of 7446 Old 04-15-2015, 12:40 AM
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Our calibration Blu-ray has this. So does Masicor's disc and I believe Ted's disc. Other discs have ColorChecker patterns, though the precise RGB values may be slightly different.


Yes, there Color Checker + Color Checker Skin Tones Chapters.
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Ted's LightSpace CMS Calibration Disk Free Version for Free Calibration Software: LightSpace DPS / CalMAN ColorChecker / HCFR
S/W: LightSpace CMS, SpaceMan ICC, SpaceMatch DCM, CalMAN 5, CalMAN RGB, ChromaPure, ControlCAL
V/P: eeColor 3D LUT Box - P/G: DVDO AVLab TPG
Meters: JETI Specbos 1211, Klein K-10A, i1PRO2, i1PRO, SpectraCAL C6, i1D3, C5
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post #6449 of 7446 Old 04-15-2015, 08:13 AM
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Of Course, ChromaPure Blu-Ray Disc is just perfect for the ColorChecker but you'll be very happy with Ted's Disk as you'll find the Skin Tones section also (and a lot of very nice patterns to check your calibration too).
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post #6450 of 7446 Old 04-17-2015, 01:29 AM
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Dear TOM!
1) What %background APL and ARL in yuor wonderfull calibration disk?
2) Why in the gamma is not possible to separate output by color -red, green, blue?
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