Highlighted
t6ho
1 Nickel

U2413 Terrible Calibration Result

Hello All,


I recently got my x-rite i1Display Pro and calibrated my U2413, but the result was terrible for adobeRGB calibration. My calibration for "native" (used EDID generated from dispcalGUI) and sRGB turned out fine.

Here's what I did:

1. Factory reset monitor

2. Disassociated all ICC profiles in Windows (I run Windows 7)

3. Calibrated with DCCS 1.5.3 (newer version couldn't "find" my display)

a. For "native", I manually entered RGB x,y taken from EDID generated with dispcalGUI; WP 0.313, 0.329; 120 cd/m; Bradford, Version 2, Table based; Large patch set

b. For adobeRGB and sRGB, I simply selected the respective preset from drop down menu; and the rest was same as "native" calibration

4. Verified results with dispcalGUI 3.0.4.2 (latest version)

a. RG_Phosphor for correction; verify_extended.ti1 testchart

d. I made sure the ICC profile was set as default in Windows; "Current" was chosen under Settings in dispcalGUI

The results:

1. "Native": https://www.dropbox.com/s/t5ahe8y2gw6dbka/Measurement%20Report%203.0.4.2%20%E2%80%94%20DELL%20U2413%...

2. sRGB: https://www.dropbox.com/s/hab4sousp7km9zd/Measurement%20Report%203.0.4.2%20%E2%80%94%20DELL%20U2413%...

3. adobeRGB: https://www.dropbox.com/s/0qa6dydv1e8ic8g/Measurement%20Report%203.0.4.2%20%E2%80%94%20DELL%20U2413%...

I've done calibrations and verification multiple times for all 3 RGB primaries and results are still the same: terrible for adobeRGB.

Am I missing something or doing anything wrong?

Also, another question, how do I check my calibrated gamut coverage with dispcalGUI?

0 Kudos
16 Replies
yumichan
3 Silver

RE: U2413 Terrible Calibration Result

Contrast is bad, but is hard to know if its due to DCCS of bad native uncalibrated monitor's state.

Since your unit is factory reseted, change to "Standard" OS mode (or "Custok color" without modifcations of RGB gian/offset), and then check it *** DispcalGUI in "tools->uncalibrated factory report". This will print in a log window native white point, primaries and constrast.

If white point is far from D65 target, contrast will drop from "uncaibrated state" and it's not DCCS fault, but poor monitor performance. Same applies to black point.

Your reports have not been measured in a proper way. "RG_phosphor" spectral correction NEED to be applied. Re do ALL of them.

To check gamut coverage (by eye seems right in last plot of each report...even if you didn't measure your monitor properly) you can check it with DispcalGUI/ArgyllCMS in several ways:

-profile info with dispcalGUI, select "relative colorimetric" since i1Profiler and DCCS are "PCS white d50" profiles and that tool ("profile info") tools does not plot PCS x CHAD matrix.

It can generate a 3D VR plot too.

-command line argyllcms

-"profile only" CAL1/CAL2, without calibration. In DispaclGUI 2.x is easier to do than 3.x, read program documentation.

0 Kudos
t6ho
1 Nickel

RE: U2413 Terrible Calibration Result

I did an Uncalibrated Factory Measurement for "Standard" mode after factory resetting the monitor and unassociated all ICC profiles in Windows. This is what I got:

16:04:31,015 Uncalibrated response:
16:04:31,017 Black level = 0.3838 cd/m^2
16:04:31,018 50%   level = 60.51 cd/m^2
16:04:31,020 White level = 280.59 cd/m^2
16:04:31,021 Aprox. gamma = 2.21
16:04:31,024 Contrast ratio = 731:1
16:04:31,026 White chromaticity coordinates 0.3006, 0.3226
16:04:31,028 White    Correlated Color Temperature = 7276K, DE 2K to locus =  8.1
16:04:31,029 White Correlated Daylight Temperature = 7275K, DE 2K to locus =  4.4
16:04:31,031 White        Visual Color Temperature = 6875K, DE 2K to locus =  7.8
16:04:31,033 White     Visual Daylight Temperature = 7072K, DE 2K to locus =  4.2

I think (?) it looks fine; at least the White Point is not too far off.

I did the Verification again, adobeRGB calibration is still "NOT OK". here are the results:

"Native": https://www.dropbox.com/s/l2oa89jut8543s7/Measurement%20Report%203.0.4.2%20%E2%80%94%20DELL%20U2413%...

adobeRGB: https://www.dropbox.com/s/ieu9wxjslt0bwz6/Measurement%20Report%203.0.4.2%20%E2%80%94%20DELL%20U2413%...

sRGB: https://www.dropbox.com/s/d4i6f7q7yrleuv7/Measurement%20Report%203.0.4.2%20%E2%80%94%20DELL%20U2413%...

This time, I double checked to make sure I selected RG Phosphor before each verification. Let me know if it's still wrong. Here's the screen shot:

Regarding the gamut coverage, I ran a "Profile only" on the "Native" calibration and I got 99.8% and 98.5% coverage for sRGB and adobeRGB respectively. That seems right like you said.

0 Kudos
yumichan
3 Silver

RE: U2413 Terrible Calibration Result

It seems that your unit has a low contrast ratio. Uncalibrated standard mode usually is ~9xx:1 (nominal value of 1000:1 in specs) and goes to ~7xx:1 once WP, BP & gamma are corrected by DCCS. So IMHO contrast ratio of your unit (from factory, not due to calibration) is LOW.

I do not know Dell exchange policies regarding this matter, for softprofing/printing it's OK but for video/web a cheap U2415 performs better by far.

aRGB report looks like you put a window over measurement place (or click on windows taskbar so desktop was visible). Re run an aRGB report or calibrate it again, that kind of deviations from grey seen on report shpuld be spotted by sight. In internet explorer, NOT a color managed browser like firefox, look at :

www.lagom.nl/.../gradient.php

If this awkward aRGB greys persist after recalibration, you can use native gamut with Photoshop (PS) or Lightroom.

0 Kudos
t6ho
1 Nickel

RE: U2413 Terrible Calibration Result

My monitor was purchased a while back, so it's way past the exchange/return period. Is there any other way to improve the contrast?

I recalibrated with adobeRGB preset and ran verification again, result is still the same.

https://www.dropbox.com/s/gl9iwemje3mmou4/Measurement%20Report%203.0.4.2%20%E2%80%94%20DELL%20U2413%...

There was no window over the measurement area and the desktop wasn't show, just DCCS.

I went to the Gradient page on IE, it looks fine by my eyes. So I really don't know what the issue is because it's only the aRGB calibration report that's messed up. I guess I'll just use "native" profile or sRGB when needed. Lightroom is what I mainly use anyway, so it's not a big deal if I use "native".

0 Kudos
yumichan
3 Silver

RE: U2413 Terrible Calibration Result

Contrast could be kept close to "native" (standard uncalibrated screen report) if using "Custom Color" OSD mode (native gamut) and GPU calibration. Without an AMD (gamer or Firerpo) or a Quadro graphics card you'll get horrible banding artifacts, this is an issue of intel and geforce cards al ALL monitors, not dell's.

Anyway, your native white is NOT close to D65 by far (White Correlated Daylight Temperature = 7275K, DE 2K to locus =  4.4) so contrast will drop from 731:1 to >65x:1 even using GPU calibration

0 Kudos
t6ho
1 Nickel

RE: U2413 Terrible Calibration Result

I have an AMD Radeon HD 6900 Series GPU. How do I do a GPU calibration? With the i1 device as well?

If the native white is off too and contrast would still drop, what is your recommendation on what I should do, yumichan? Go with the GPU calibration? Factor it in while I edit my photographs in Lightroom? Or something else?

Thank you very much!

0 Kudos
yumichan
3 Silver

RE: U2413 Terrible Calibration Result

You tested Standard mode response, I think I said it in previous messages but for GPU calibration in native gamut you should use "Custom color" OSD mode. Then with RGB gain 100% and offset at 50%, contrast 50% and your default/prefered brightness setting run uncalibrated report like you did before

It should be the same as Standard... white & contrast ratio

To perform GPU calibration I use ArgyllCMS/DispcalGUI (last one it's just a windows user interface that uses ArgyllCMS commands in background). Lots of examples of configuration in the net, checkout official websites.

You can use i1Profiler if you found it friendlier.

Then while running these programs your 1st step is to manually adjust RGB gain/offset of "Custom color mode". i1Profiler can do it for your automatically but manually you can maximize contrast.

Since your native white looks like usual native GB-LED cool white, Blue and green channels should be lowered. These calibration programs have a "visual" indication of how much. For example RGB gain R100,G93,B97 for D65. This will drop contrast a little, but not as much as DCCS (it seems that it aims to 47% OSD contrast setting for unknown reasons choosed by Xrite, plus near black calibration contrasts loss).

RGB offset can be used for finetune white point and/or to fix black point. Lots of options here... but for a 1st approcah do not modify them, factory setting 50%.

You can "lift" a little Contrast OSD value to 55%, 57%, but this action will push "active" emiters up (Green and blue leds) giving a cooler white, so lower settings for RGB gain should be used on that channels. Calibration software will report these things  too. A value too high may worsen overshoot problen on these Dells, <70% should be fine.

Native gamut "Custom color" calibration to D65, 2.2 gamma is a pretty straightforward process. It should be no difficult for you.

0 Kudos
t6ho
1 Nickel

RE: U2413 Terrible Calibration Result

yumichan, I ran an uncalibrated report for "Custom Color" OSD mode, but the White and Contrast are not same as the "Standard" OSD mode:

12:47:51,959 Uncalibrated response:
12:47:51,961 Black level = 0.3876 cd/m^2
12:47:51,963 50%   level = 65.96 cd/m^2
12:47:51,967 White level = 312.76 cd/m^2
12:47:51,968 Aprox. gamma = 2.25
12:47:51,969 Contrast ratio = 807:1
12:47:51,971 White chromaticity coordinates 0.2954, 0.3428
12:47:51,972 White    Correlated Color Temperature = 7298K, DE 2K to locus = 17.8
12:47:51,973 White Correlated Daylight Temperature = 7281K, DE 2K to locus = 16.0
12:47:51,974 White        Visual Color Temperature = 6382K, DE 2K to locus = 17.4
12:47:51,975 White     Visual Daylight Temperature = 6504K, DE 2K to locus = 15.6

Anyway, I went ahead and tried a GPU calibration. Not sure if I did it correctly, but this is what I did:

When Interactive Display Adjustment window came up, I set RGB Gain at R100 - G88 - B94, Brightness 22% and Contrast 57%. I left RGB Offset at default.

After the calibration was done, I verified the result:

https://www.dropbox.com/s/phit4dn3413s0bw/Measurement%20Report%203.0.4.2%20%E2%80%94%20DELL%20U2413%...

Like you said, contrast is ~65X:1. Is there anymore I can do or will this be the best I can get?

On another note, I wanted to check the Gamut Coverage for the GPU Calibrated Profile (since I forgot to check it when the window pops up).

Somehow I couldn't find the "Profile Only" option this time. I was able to before from the Interactive Display Adjustment, I didn't click on "Start measurement" and instead of "Continue on to calibration", it was "Continue on to profiling". I looked through the program manual again, this is what it reads: "If you only wanted help to adjust the display and don't want/need calibration curves to be created, you can also choose to exit by closing the interactive display adjustment window and then select “Profile only” from the main window." There is no "Profile only" on the main window.

Could you give me a quick rundown, please?

And you mentioned my native white is not close to D65 because White Correlated Daylight Temperature = 7275K, DE 2K to locus =  4.4 (from Standard mode uncalibrated report), the temperature should be near 6506k, right?

0 Kudos
yumichan
3 Silver

RE: U2413 Terrible Calibration Result

I think that is one of the best contrast result you'll get with your unit.

Pushing up contrast may "overpower" green channel in your unit (blue led spectra gently falls into cyan-greens, so pushing up blue led by contrast pushes up a little greens), hace you need to drop to 88% RGB gain.

Before you press "Continue with calibration" you can cancel calibration and with white point corrected via RGB gain OSD menu (D65), run an UNcalibrated screen report. If you run that report right now (after calibration) it will disable GPU LUTs (and calibration) so the test will be the same. There you will get "white calibrated", "gamma uncalibrated" monitor status and contrast. Lest call X that contrast value

807:1 -> X is the contrast lost due to whitepoint correction (contrast OSD + RGB GAIN).

X -> 658:1 (Measurement Report 3.0.4.2 — DELL U2413 @ 0, 0, 1920x1200 — 2015-09-16 17-25 Custom OSD3.html) is the contrast lost in gamma and grey neutralization correction.

If X is around 750-6xx:1, I find very dificult to improve contrast results on that unit, you're on its limits.

***

There should be a command line in ArgyllCMS to generate gamut coverage values of your calibrated profile ICM file to ANY colorspace defined in a ICM (sRGB, AdobeRGB, eciRGBv2...).

Since DispcalGUI 3.x "Profile only" button was removed. I find more intuitive 2.6 version with old user interface...

In 3.x there is a long workaround where you need to set native white point, native gamma and a few more combos that I do not remember. Then select in uper combo " .cal" file with your gamma and grey calibration of your profile and redo calibration. That kind of configuration "should" skip calibration step applying calibration stored in that ".cal" file and go to "profiling"  stage (measurement of calibrated monitor's behaviour).

It's faster to ask Graeme Hill in ArgyllCMS maillist to a comandline that performs coverage checks. Gamut plot seems OK anyway and you retain >95% grey values with a GPU that performs dither in a >=10bit lut, so I won't bother


*****************

"And you mentioned my native white is not close to D65 because White Correlated Daylight Temperature = 7275K, DE 2K to locus =  4.4 (from Standard mode uncalibrated report), the temperature should be near 6506k, right?"

There you have 2 values. One correlated color temp... in order to explain it easy, think of it as yellow blue axis. Second one is of far you are in pink-green axis from "A WHITE" (cool white, warm white) of that temperature.

7000K 0.9dE to daylight locus is WHITE, cool white but "white" and could be easily corrected to D65.

6506K 10dE to daylight locus is NOT white, may be pink or green if it goes to one side or another of pink-green axis. 10dE states DISTANCE from whites curve (cool-warm, blue-yellow white curves)

You had "12:47:51,973 White Correlated Daylight Temperature = 7281K, DE 2K to locus = 16.0" which is far from both of the two coordinates. A cool white moved to green. It's pretty common of native unmodified factory uncalibrated GB-LED response (maybe in your unit is too much off) but with 1000-900:1 uncalibrated contrast is easy to achieve D65 keeping a >850:1 contrast.

Your unit seems to have:

-native low contrast, compared to other units

-native white cooler and greener than other units

so it's hard to improve your DispcalGUI result.

For printing purposes I would NOT bother, since in that sutuations you want a "paper contast" of 300:1, D50 white. DCCS cannot do that, since it has no contrast control, it should be done with DispcalGUI or i1Profiler.

0 Kudos