Basic Guide to Color Calibration using a CMS (updated and enhanced) - Page 61 - AVS Forum
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post #1801 of 1936 Old 05-10-2012, 10:26 PM
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My only beef with dE is that it only tells you the magnitude of the error and not the direction of the error(s).

Say you have two points (to keep it simple: 10% and 20% on your greyscale.)

Say both have a dE of 2.5, but the 10% point is +Blue while the 20% point is +Red ... now you have an effective relative dE of 5.0 ...

Now imagine the chaos that could happen when you rely on multiple dE calculations around the gamut to figure out if you have your CMS setup "right."
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post #1802 of 1936 Old 05-11-2012, 04:52 AM
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Quote:
Originally Posted by HDTVChallenged View Post

My only beef with dE is that it only tells you the magnitude of the error and not the direction of the error(s).

Say you have two points (to keep it simple: 10% and 20% on your greyscale.)

Say both have a dE of 2.5, but the 10% point is +Blue while the 20% point is +Red ... now you have an effective relative dE of 5.0 ...

Now imagine the chaos that could happen when you rely on multiple dE calculations around the gamut to figure out if you have your CMS setup "right."

dE is used in combination with actual measurements of RGB relative levels for grayscale
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post #1803 of 1936 Old 05-11-2012, 10:24 AM
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Originally Posted by PlasmaPZ80U View Post

dE is used in combination with actual measurements of RGB relative levels for grayscale

Yes ... but it's very easy to get caught up in chasing the dE's while neglecting to watch the relative shifts. IOW your "D65" @ 20% might not be the same "D65" you have @ 80%. And it gets crazier once you dive down CMS rabbit hole, especially as the calibration session drags on and fatigue sets in.
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post #1804 of 1936 Old 05-11-2012, 10:33 AM
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Quote:
Originally Posted by HDTVChallenged View Post

Yes ... but it's very easy to get caught up in chasing the dE's while neglecting to watch the relative shifts. IOW your "D65" @ 20% might not be the same "D65" you have @ 80%. And it gets crazier once you dive down CMS rabbit hole, especially as the calibration session drags on and fatigue sets in.

that's why adjustments are made while looking at the actual data and dE is used afterwards to tell you when you're done... dE on its own doesn't tell the whole story but if you use a good formula it will complement looking at the actual grayscale or gamut data/charts/graphs

However, I'd say if you can get grayscale flat across the entire range and within a couple percent of the 100% target line, you wouldn't need to worry about such things at all. Most sets can get close enough to an ideal, flat grayscale that what you mention becomes a non-issue.
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post #1805 of 1936 Old 05-11-2012, 02:32 PM
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Do this work in the ChromaPure Gamma module. It's all there on one page: gamma, GS balance, and dE.

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post #1806 of 1936 Old 01-01-2013, 12:24 PM
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What are the cons of using a meter in contact, versus non-contact, on a plasma? I am thinking specifically of using an EyeOne Display 3.
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post #1807 of 1936 Old 01-01-2013, 02:21 PM
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Quote:
Originally Posted by HD-Master View Post

What are the cons of using a meter in contact, versus non-contact, on a plasma? I am thinking specifically of using an EyeOne Display 3.

Tom says "NO" to contact/plasma!


bob
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post #1808 of 1936 Old 01-01-2013, 02:26 PM
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Quote:
Originally Posted by spongebob View Post

Quote:
Originally Posted by HD-Master View Post

What are the cons of using a meter in contact, versus non-contact, on a plasma? I am thinking specifically of using an EyeOne Display 3.

Tom says "NO" to contact/plasma!


bob

I'm getting that impression, but haven't found his comments on why yet.
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post #1809 of 1936 Old 01-01-2013, 02:37 PM
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Plasmas put out a lot of heat which will affect the life of a meter in contact as well as influence readings as it heats up.

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post #1810 of 1936 Old 01-01-2013, 02:45 PM
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Originally Posted by JimP View Post

Plasmas put out a lot of heat which will affect the life of a meter in contact as well as influence readings as it heats up.

Thanks. I wasn't sure if that was the case with the EyeOne Display 3. Is there some rule of thumb for how far I should place the meter from the display?
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post #1811 of 1936 Old 09-02-2013, 05:18 PM
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I just finished my first 10 point grayscale and primary color calibration with pretty good results. (TC-P50ST60) But I have a possibly dumb question (See the very bottom of this post).




(The lone dot that isn't right on top of D65 is IRE 0, the rest are right on top of D65)

Still need to calibrate gamma though:



The only question I have now though is, when I'm using the 10 point gamma controls, what value(s) should I be looking at in HCFR while taking continuous readings? I don't want to have to sample my gray scale every single time I make an adjustment to that menu just to see the changes reflected. Maybe I'm just blind but I can't seem to find any detailed instructions on calibrating gamma at all... Although my average gamma came out at exactly 2.22, I want to have it a flat 2.22 or try to go for BT. 1886.
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post #1812 of 1936 Old 09-02-2013, 05:41 PM
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Use this calculator: http://www.avsforum.com/t/1409045/how-power-law-gamma-calibration-can-lead-to-crushed-blacks/90#post_22208270
Enter your black and white measurements at the top left and take note of the luminance for each % stimulus in the table below. Now use the continuous read and use the gamma gain to adjust the luminance (Y value) to match the numbers in the spreadsheet for each % stimulus.

If you don't have an excel (.xls) viewer, use this online excel viewer: https://sheet.zoho.com/excelviewer

Once you're done, double check everything and make any fine tuning adjustments if necessary.
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post #1813 of 1936 Old 09-02-2013, 05:48 PM
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Quote:
Originally Posted by rahzel View Post

Use this calculator: http://www.avsforum.com/t/1409045/how-power-law-gamma-calibration-can-lead-to-crushed-blacks/90#post_22208270
Enter your black and white measurements at the top left and take note of the luminance for each % stimulus in the table below. Now use the continuous read and use the gamma gain to adjust the luminance (Y value) to match the numbers in the spreadsheet for each % stimulus.

If you don't have an excel (xls) viewer, try this: https://sheet.zoho.com/excelviewer

Ah, Thanks so much!
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post #1814 of 1936 Old 09-02-2013, 06:21 PM
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Hmm nevermind... this doesn't really help me. I suck at math... Do most people just make the settings then recheck their grayscale or what?
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post #1815 of 1936 Old 09-02-2013, 06:30 PM
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There's no math required... the spreadsheet does it for you. It's just a matter of matching your luminance (Y) to the numbers in the spreadsheet for each % stimulus. In continuous read mode in HCFR, the luminance (Y) is in the bottom left table.
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post #1816 of 1936 Old 09-02-2013, 06:57 PM
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Quote:
Originally Posted by rahzel View Post

There's no math required... the spreadsheet does it for you. It's just a matter of matching your luminance (Y) to the number in the spreadsheet. In continuous read mode in HCFR, the luminance (Y) is in the bottom left table... just match that number to the spreadsheet at each % stimulus.

I tried that, but it doesn't match up right. For one the Y value was always higher than on the spreadsheet, even when the gamma needed to go the other way. I tried adjusting to those Y values anyway and it just lowered my gamma overall as I expected.
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post #1817 of 1936 Old 09-02-2013, 07:09 PM
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Did you enter your black and white measurements (luminance of black and white) in the top left (green) box? The points should match... I have no idea why they wouldn't.
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post #1818 of 1936 Old 09-02-2013, 07:11 PM
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Quote:
Originally Posted by rahzel View Post

Did you enter your black and white measurements (luminance of black and white) in the top left (green) box? The points should match... I have no idea why they wouldn't.

Oops. I did not enter those right.

Thanks again biggrin.gif
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post #1819 of 1936 Old 09-02-2013, 07:13 PM
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Quote:
Originally Posted by damag0r View Post

Oops. I did not enter those right.

Thanks again biggrin.gif


The information that rahzel is giving you is all correct. However, HCFR does all the calculations for you. Look at the row labeled GammaY. That tells you what values you need for your resulting grayscale 100% Y (and, in the case of bt.1886, the value at 0%.)

BTW, this is the wrong thread for this discussion. Since you are asking about the HCFR program, post it in: http://www.avsforum.com/t/1393853/fork-of-hcfr-started-whats-needed.

Larry
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post #1820 of 1936 Old 09-02-2013, 07:54 PM
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I thought that row only told you your measured luminance? Too lazy to unpack my meter to check. tongue.gif
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post #1821 of 1936 Old 09-02-2013, 08:02 PM
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post #1822 of 1936 Old 09-02-2013, 08:18 PM
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Oops, my mistake.
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post #1823 of 1936 Old 09-03-2013, 07:56 PM
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I’m late to the thread (!) but if you want my very short introduction to so-called CMS in CE, consult 6-axis colour correction.

While I’m here, I’d like to make two requests: Please don’t use the term luminance to refer to the video signal that conveys the achromatic (greyscale, “black-and-white”) colour component; use luma instead. And, please don’t use the term stimulus to refer to any video signal. Use video signal or just video (for example, “75% video”) instead. Details at Two requests of home theatre enthusiasts.

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post #1824 of 1936 Old 09-13-2013, 11:41 AM
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I do not believe that on a Panasonic VT50 with CMS the basic color/tint controls are redundant or obsoleted.

After calibrating a color, (I've only tested this on red), I found that the lower saturation levels were scaled differently depending on the main color setting. Intuitively it makes sense, like the CMS "red" control has an increasing affect as you approach pure red, but the main color control just blindly gains the color components before adding them to Y.

Edit: This isn't a VT50 thread and I can't suggest this as a tip for that display because I haven't fully explored the side effects. For example I have no idea what it did to Y values or other colors. The only point here is that it did something that mattered - which can't be done AFAIK with CMS alone.
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post #1825 of 1936 Old 09-20-2013, 04:40 AM
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Guys a quick question, Im looking at spectracal c6 and i1pro2, which one should I get so I can do everything, from gray scale pattern to color Gamut. Im currently using i1d2, seem like this meter dont do well with color space adjustments
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post #1826 of 1936 Old 09-20-2013, 07:08 AM
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Quote:
Originally Posted by kanti123 View Post

Guys a quick question, Im looking at spectracal c6 and i1pro2, which one should I get so I can do everything, from gray scale pattern to color Gamut. Im currently using i1d2, seem like this meter dont do well with color space adjustments
Get an i1pro2 or even an i1pro rev.D... they will be more accurate on various display types. The C6 has the advantage of speed and low-light reading, but you can always get a D3 later and profile it to your spectro.
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post #1827 of 1936 Old 09-20-2013, 11:14 AM
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Quote:
Originally Posted by kanti123 View Post

Guys a quick question, Im looking at spectracal c6 and i1pro2, which one should I get so I can do everything, from gray scale pattern to color Gamut. Im currently using i1d2, seem like this meter dont do well with color space adjustments

Quote:
Originally Posted by rahzel View Post

Get an i1pro2 or even an i1pro rev.D... they will be more accurate on various display types. The C6 has the advantage of speed and low-light reading, but you can always get a D3 later and profile it to your spectro.

and he could profile the i1D2 now to a Spectro (and when budget allows in the future, go with the i1D3 / Spectro combo.

As far as meters, I always recommend a i1Pro Spectrometer, even a used i1Pro Rev D ($250-$450) is great.

Why a Spectro, see why here:

http://www.avsforum.com/t/1373556/i1-pro-or-d3-if-you-could-only-have-one-meter

http://www.tlvexp.ca/2012/04/do-calibration-tables-really-work-for-tri-stim-devices/

And Read these Threads:
http://www.avsforum.com/t/1449310/eye-one-pro-or-display-3-pro

http://www.avsforum.com/t/1464411/what-would-you-rather-have-for-display-calibration

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post #1828 of 1936 Old 09-20-2013, 09:07 PM
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Thanks for the quick reply, seem like i1pro2 is out of stock on spectracal site. I could figure a way to keep my self from getting eye strain, and with samy setting constrast lower than 90s messes up the gamma and 10p white balance seem to not working. Would it be best to calibrate it normally then turn on eco sensor so the tv can just dim the screen accordingly?
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post #1829 of 1936 Old 10-14-2013, 06:24 AM
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For calibrating a plasma display using hcfr software and an i1 display sensor, can I start a cnibration at night in complete darkness and then continue it in daylight (no direct sunlight on the screen though)?

Or am I better off continuing it at night again?

The. I1 is pushed up directly on the screen.
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post #1830 of 1936 Old 10-14-2013, 06:29 AM
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Quote:
Originally Posted by Sittler27 View Post

For calibrating a plasma display using hcfr software and an i1 display sensor, can I start a cnibration at night in complete darkness and then continue it in daylight (no direct sunlight on the screen though)?

Or am I better off continuing it at night again?

The. I1 is pushed up directly on the screen.

it's better to calibrate at night in totally dark room if it's like your viewing conditions wink.gif
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