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Author Topic: Monitor calibration sensor evaluations  (Read 69732 times)
shewhorn
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« Reply #160 on: October 31, 2011, 07:15:46 PM »
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It's something different - CCFL backlight also needs some time for stabilisation, so it may drift a bit in a period of time between calibration and validation. That's why you get consistent results and lower deltas in next runs - you can also check "Extended luminance stabilization time" in SpectraView II Preferences>Calibration tag.

I've noticed most larger CCFL lit monitors can take around 45 minutes to stabilize. For this reason I never bother calibrating and profiling in the morning. When I need to cal, it's the very last thing I do at the end of the day before I turn the machine off, that way I never have to guess as to whether or not the monitor is warmed up.

Cheers, Joe
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shewhorn
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« Reply #161 on: October 31, 2011, 07:18:46 PM »
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Joe, thanks for the work on this. 

My pleasure although... Ethan deserves all the thanks here. When you consider all the multiple pucks and multiple monitors, I'm guessing the number of hours he's put into this is probably around the 160 hour mark if not more. This information is of tremendous value.

Cheers, Joe
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ThDo
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« Reply #162 on: November 01, 2011, 01:52:21 AM »
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Any clues why you get such a huge difference between i1 Pro and i1 Display Pro?

I have tried your approach and get the following values.

i1 Display Pro
6509K at 107.94 cd/m˛

i1 Pro
6482K at 109,32 cd/m˛

Spyder 3
6976K at 108,54 cd/m˛

« Last Edit: November 01, 2011, 02:03:30 AM by ThDo » Logged
Ernst Dinkla
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« Reply #163 on: November 01, 2011, 03:28:16 AM »
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Ethan deserves all the thanks here. This information is of tremendous value.

Cheers, Joe

Yes, the testing and this thread is the best information available for anyone that needs color correct monitors. Ethan has done a brilliant job.


met vriendelijke groeten, Ernst

330+ paper white spectral plots including the Canon US catalog:

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
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Ethan_Hansen
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« Reply #164 on: November 01, 2011, 08:52:36 AM »
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Thanks to all for the kind words. Much appreciated.

Joe: I'll look into your latest data later -  typing on my phone while waiting for a flight isn't conducive to number crunching.  Taking a SWAG at it, the numbers look reasonable for luminance. Color temp I am not so sure about. The variation you see between i1Pro and i1D3 are certainly within the range we have seen. The NEC puck just plain looks bad. The luminance value should be more in line with the rest. Shoot me a PM with your snail-mail and I will send you an i1D3 w measured as being in the middle of the pack.

Other quick comments: The huge offset of the i1d2 from the other instruments is not surprising. See the chart in the first post of this lengthy thread. The unit-to-unit variability we measured on the i1d2 is large. As far as I can ascertain, NEC does not calibrate each i1d2 individually.

An i1 Pro is one of the more temperature sensitive instruments. Letting it stabilize at monitor temp and then calibrating is essential for accuracy.
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fetish
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« Reply #165 on: November 11, 2011, 02:00:40 PM »
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This thread is one of the most informative and wonderful thread I've read. Enjoyed it immensely.


Dell makes offhand mention of DDC in the online documentation. From what I have been told, the problem with DDC and Dell stems from Dell's transfer of all firmware development to a new group when the transition from CRT to LCD occurred. Some LCD Dell monitors returned an EDID (the "Extended Display Identification Data" tag used to identify a particular panel) for a previous generation CRT. There are other quirks with Dell's DDC implementation, of which their own engineers may or may not be aware.

Slightly off the topic but yes it seems that quite a few Dell ultrasharp monitors have DDC built in them but they posses nowhere near the implementation of NECs and Eizos.
To be honest it's a horrible hit and miss (more miss than hits) affair everytime I tried to take advantage of DDC using CEDP that I dismissed using it entirely.
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Ethan_Hansen
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« Reply #166 on: November 11, 2011, 09:56:46 PM »
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Slightly off the topic but yes it seems that quite a few Dell ultrasharp monitors have DDC built in them but they posses nowhere near the implementation of NECs and Eizos.
To be honest it's a horrible hit and miss (more miss than hits) affair everytime I tried to take advantage of DDC using CEDP that I dismissed using it entirely.

The last I heard, the guys at Integrated Color (makers of CEDP) gave up on talking to Dell. At least two other monitor profiling software vendors I am aware of are working actively on cracking DDC on Dell UltraSharp displays. As I mentioned above, there is serious confusion within Dell regarding DDC.

On Windows, CEDP uses a DDC driver from Portrait Displays. It is outdated and tied all too much to individual graphics cards. The most recent video cards specifically supported were introduced in 2006 (NVIDIA 8800). No clue whether an update to the DDC code will be forthcoming. We can hope.
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Tim Lookingbill
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« Reply #167 on: November 13, 2011, 11:31:13 AM »
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Ethan,

I'ld be interested in your thoughts on this thread I started...

http://www.luminous-landscape.com/forum/index.php?topic=59388.msg479174#msg479174

Do you think my buying the i1Display Pro would fix these issues I've been having and deliver better Delta E numbers?
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ComputerDork
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« Reply #168 on: November 28, 2011, 07:51:23 PM »
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I don't have anything to add at this point, but my eternal thanks for both performing such thorough evaluations and then making them publicly available. This is incredibly useful! I'm now kind of wishing that I had bought a ColorMunki first (for printer profiling and reasonably OK monitor profiling) then an i1 Display Pro when I bought my NEC PA241 (instead of the OEM MDSVSESOR2).
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Czornyj
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« Reply #169 on: January 03, 2012, 03:48:51 AM »
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There's a new Spyder4 colorimeter out there.

Ethan, when could we count to hear something about new device from you?
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mac_paolo
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« Reply #170 on: January 03, 2012, 05:19:38 AM »
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There's a new Spyder4 colorimeter out there.
Any link?  Huh
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Czornyj
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« Reply #171 on: January 03, 2012, 06:32:09 AM »
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http://shop.colourconfidence.com/section.php/10684/1/new-spyder4-range
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uwitberg
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« Reply #172 on: January 06, 2012, 05:30:07 AM »
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There's a new Spyder4 colorimeter out there.

Datacolor have updated their website by now:
http://spyder.datacolor.com/product-mc.php
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mac_paolo
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« Reply #173 on: January 08, 2012, 03:17:35 AM »
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Datacolor have updated their website by now:
http://spyder.datacolor.com/product-mc.php
Oh boy... I bought the i1Display Pro 3 days ago. I costed 50€ than advised price for Spyder4 Elite.
Should I return the former one to get the latter and keep the difference?  Wink
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digitaldog
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« Reply #174 on: January 08, 2012, 11:13:06 AM »
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The i1D Pro is an excellent piece of hardware. Unless you have data to prove the other product is as good or better, I’d stick with what you have.
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Andrew Rodney
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Czornyj
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« Reply #175 on: January 08, 2012, 11:15:12 AM »
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Oh boy... I bought the i1Display Pro 3 days ago. I costed 50€ than advised price for Spyder4 Elite.
Should I return the former one to get the latter and keep the difference?  Wink

I bet i1Display Pro is still better than new Spyder4, it's a very smart designed, well made sensor with advanced profiling software.
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WombatHorror
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« Reply #176 on: January 09, 2012, 02:36:50 PM »
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On a somewhat related but slightly tangential note, have you ever seen curious behaviors  in any of Dell's monitors with regards to how the monitor LUTs behave? I tested an Asus PA246Q. All things considered, for a sub $500 monitor it had some nice features... 12 bit LUT, 10 bit panel... it had two fatal flaws though:

1) It couldn't go lower than 135 cd/m^2
2) ANY change to the monitor LUTs resulted in an alarming increase in ∆E... as in average ∆E in the 10+ range.

I first noticed this when using CEDP to control it via DDC. The validation results could have been the lead character in a horror film. Multiple attempts produced identical results. DDC being what it is, I figured their implementation may not have been standard so I reset the monitor and figured I'd do it the old fashioned way, by adjusting the RGB gains and offsets by hand. This produced the same results. If you set the RGB levels to anything other than 0,0,0, the average ∆E would jump to 10+. Didn't matter if it was 1,0,0 or -20,+17,-4... any change would result in massive average ∆E.

I found this to be a rather curious behavior. A month later I tested a Dell U2410. SAME EXACT behavior. Similar specifications... 12 bit LUT, 10 bit panel (I believe they both used the same panel)... I kind of have a sneaking suspicion that Dell and Asus OEMed the guts and contracted the engineering from the same place. That's just too much of a coincidence.

Cheers, Joe

I believe one monitor review site said that the color engine in the U2410 is broken and it produces twisted messed up results if you use the custom mode and it's better to leave it in presets and adjust externally.
It would be odd if ASUS used the same driving electronics/firmware with same bug though.
Apparently the Dell U2710 has no such bug.

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WombatHorror
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« Reply #177 on: January 09, 2012, 02:52:06 PM »
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@shewhorn

Here are mine Spectraview II values.

Spyder 3: CIE 0.306, 0.338 at 114.24 cd/m˛
i1 Pro: CIE 0.313, 0.335 at 116.63 cd/m˛
i1 Display Pro: CIE 0.313, 0.330 at 114.33 cd/m˛

What did you do to see 4 decimal places?




I generally get extremely close readings from my custom NEC i1D2 and my i1Pro when using SV II to measure my NE PA241W. Over a year they don't agree quite as much at the start (when most values would be exactly the same to .000 or .001 off, I think only one or two had been .002 off) but even now it's pretty close.

I did find that I had to let the NEC i1D2 warm up for a long time, 15 minutes was NOT enough for it to closely match my i1pro. I let it warm for 45 minutes and then, with the monitor in native gamut mode/photo editing, measured:

i1pro:
WP .313,.330 6503K
R .679, .309
G .214, .690
B .152, .056

and the custom NEC i1D2 (and I believe they DO custom calibrate each copy, they have implied that, and I'd have to be awfully luck to have such close matching I think, and the price for them would be a remarkable rip-off otherwise and the difference between stock i1D2 and their i1D2 is the same as many place charge for a custom calibration):
WP .315, .330 6376K
R .683, .306
G .214, .691
B .152, .057

and comparing sRGB emulation mode:
i1pro:
.639, .330
.301, .599
.152 , .061
.312, .329
whle i1d2 said:
.642, .328
.303, .600
.152,.061
.315,.331

so the differences have certainly grown over the past year, when both were new, as I said, many values were .000 and the rest .001 but for a couple at .002 while nwo there are a number of .003 differences and one .004, that said there are still many .000 or .001 so the match is not too far off

In fact, it's actually only how each reads red where any difference at all lies and that is where the difference increased a little bit over teh year. For how each reads the blue and green signal, it's essentially exactly the same for both and still so a year a later.

I didn't compare luminance or gamma tracking. I didn't compare black point since the i1pro is sketchy there and tends to return a different luminance, often quite different, on every reading from SV II since it doesn't average them much.

(side note: I think when comparing probes and seeing how they do on wide gamuts, in particular, the chromaticities need to be measured and not jsut luminance and white point! For some probes it is the primaries where the measurements go really crazy on wide gamut too and not just with the WP.)

« Last Edit: January 09, 2012, 02:54:02 PM by LarryBaum » Logged
WombatHorror
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« Reply #178 on: January 09, 2012, 03:00:34 PM »
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Oscar,

We approached this in two ways. First, we evaluated each sensor on a range of screens, manually adjusting each panel to as close to a 6500K white point and 150 cd/m2 luminance level as possible. These included both CCFL and LED backlight laptops, three standard gamut CCFL, four wide-gamut CCFL, one RGB LED, and two white LED displays. We used our spectroradiometer to guide the adjustments. Depending on whether DDC was available, the screens hit the setpoint to varying degrees of accuracy.

The other approach is part of our profiling software evaluations. Here we test both the ability to hit a specified white level and match to another screen.

On top-quality, highly uniform displays if the measured difference between two screens was under 1 dE-2000, the visual match was near-perfect. On lesser displays there often are color and luminance shifts across the screen. These variations can easily exceed 5 dE-2000 on cheapo (~$300, 24") IPS panels and go even higher on on TN panels. There is no way to get a visual match between such a monitor and a reference, simply because only a small portion of the screen accurately hits the calibration target. Most high end displays have maximum variation of at least 2 dE-2000 edge to edge. You can see that.

Am I correct that you don't test them for measuring the primaries though? Only the luminance and white point?
FOr instance I saw some guys using a spyder3 and with the new software getting a semi-decent WP reading from it on a wide gamut and they thought all was good but when I had them plot the gamut the green primary was plotted way out of line.

But much thanks for all the measurements taken though, very useful stuff!!!!
« Last Edit: January 09, 2012, 10:06:50 PM by LarryBaum » Logged
Ethan_Hansen
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« Reply #179 on: January 13, 2012, 04:02:57 PM »
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We measured white (6500K, 150 cd/m2), lowest usable black (roughly the level at which [0, 0, 0] could be differentiated from [1, 1, 1]), middle gray, and the three primaries. For simplicity we only reported the results at black and white. Middle gray showed nothing of interest, and while the primary color measurements could diagnose which color a particular sensor had difficulty with (and, yes, the Spyder 3 was at its worst with green), the white point value encompassed all the primaries. After all, white is made with all three primaries turned on full.
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