Re: real world wide gamut monitor - HP LP2475w - calibration with Spyder3
Re: real world wide gamut monitor - HP LP2475w - calibration with Spyder3
- Subject: Re: real world wide gamut monitor - HP LP2475w - calibration with Spyder3
- From: Steven Dobbelaere <email@hidden>
- Date: Mon, 7 Dec 2009 17:43:40 +0100
Hi,
I have doubts about the gamut of my monitor profile. I've did some investigation but have still a lot of questions (even after reading the "Monitor Calibration" thread from a couple of weeks ago in this list).
The monitor I have is an HP LP2475w, a wide gamut display.
It uses a wide CCFL backlighting lamp and has a color gamut of 92%.
http://h10010.www1.hp.com/wwpc/uk/en/sm/WF05a/382087-382087-64283-3884471-3884471-3648442.html
In the states the gamut seems to be 102% ?
http://h10010.www1.hp.com/wwpc/us/en/sm/WF05a/382087-382087-64283-72270-3884471-3648442.html
QUESTION1: What is the reference gamut to express a gamut coverage? 92% of what gamut?
Eizo and NEC use the AdobeRGB gamut as reference, but is there a kind of an ISO to express the gamut volume?
Here they compare with the NTSC color gamut:
http://www.tftcentral.co.uk/speccontent.htm#gamut
I first used an EyeOne display2 for creating my monitor profile.
However, EyeOne Display2 devices have a specific calibration matrix when they are bundled with
high-end monitors. That is a clear indication for me that a standard device is not suited for wide
gamut displays.
Therefore I bought a Spyder3 elite because this device is suited for wide gamut displays.
http://spyder.datacolor.com/product-mc-s3elite.php
New Support for Next Generation Displays. Patented Spyder3 optical design and color engine enable precise calibration and profiling of the latest in wide gamut, LED backlight and AdobeRGB displays.
Comparing my monitor profiles measured with the EyeOne Display2 and the Spyder3 revealed some surprising results.
Settings: native white point - gamma 2.2 - brightness=100 and contrast=100 - 16-bit LUT / CAT02 / icc v4
All profiles are created with basICColor.
http://img43.imageshack.us/img43/9751/e1d2spyder3.jpg
As you see in above screenshots the gamut of the monitor profile created with the spyder3 is smaller then the EyeOne Display2.
I returned my spyder and received a new one. However, the result was the same.
I compared again the monitor profiles from an EyeOne Display2, the Spyder3, the EyeOne Pro and the Colormunki.
Again the same results:
Settings: native white point - gamma 2.2 - brightness=100 and contrast=100 - 16-bit LUT / CAT02 / icc v4
http://img51.imageshack.us/img51/5036/e1d2colormunki.jpg
http://img31.imageshack.us/img31/5659/e1d2e1pro.jpg
When i compare my profiles with profiles from other users then they are very similar.
http://img704.imageshack.us/img704/3104/e1d2othere1d2.jpg
http://img43.imageshack.us/img43/9927/spyder3otherspyder3.jpg
QUESTION2: Which profile is now most accurate?
I think this can only be answered when:
comparing with a device that uses a calibration matrix
comparing with measurement data from a spectroradiometer
What i have is the EDID info from the monitor (I assume not from my monitor but for all HP LP2475w monitors).
When i make a profile with these values and compare it then the Spyder3 profile is closer to the gamut of the EDID profile in the part
where the E1D2 is much larger.
http://img51.imageshack.us/img51/3520/comparedwithedid.jpg
What I actually expect is a profile that is covering most of the AdobeRGB gamut.
THe Spyder 3 should be the recommended tool, but it fails and the I1D2 profile is much larger??
http://img704.imageshack.us/img704/9219/spyder3versusadobergb.jpg
http://img704.imageshack.us/img704/8173/eyeonedisplay2versusado.jpg
When I use the volume values then I get a coverage of 111% for the I1D2 profile and a coverage of 98% for the Spyder3 profile.
Good, the gamut value is not that bad but what does it tell me? If the gamut coverage of a monitor is 92% then the 92% can be:
- inside the reference gamut
- partly inside the reference gamut
QUESTION3: Am I correct that the gamut value doesn't tell how well the reference shape is followed?
QUESTION4: Is there a reference wide gamut (CCFL) profile available created with a spectroradiometer that I could use to see how accurate my
colorimeter is?
THx!
Steven
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