Help: Bought used monitors but is temperature differences within tolerance?

Hi,

I have two monitors. I set them up and then used my i1Profiler to calibrate both monitors. Then I started working on a black and white image in LR. I had the same image opened on both monitors and I noticed they were different colors! After some VERY extensive subjective testing I figured out that the right side of monitor #1 is significantly bluer than the left side/middle. Monitor #2 appeared to my eyes more even, and in general warmer than monitor #1.

I recalibrated both monitors like 5 times each. I also tried different settings of contrast, and tweaked the RGB values extremely carefully during manual adjustment. I am pretty sure I did the calibration correctly.

So... then I got an idea. I started up the profiler but when it got to the RGB adjustment phase, it also shows temperature. So, I used that to measure the temperature of different regions of the monitors:

Monitor #1:

middle 6526
top 6400
bottom 6660
left 6594
right 6656

Monitor #2:

middle 6616
top 6300
bottom 6885
left 6756
right 6558

Note: both "middle" values were very near 6500 from the previous calibration, so that's kinda weird to me already.

So, ...I am thoroughly confused. Monitor #1 does measure to be colder on the right. However, monitor #2 has much more variation left to right, and that's not what my eyes see.

Anyway, does anyone know if the variation in temperature across the different areas of the surface is within tolerance of a mid/high-end 99% Adobe monitor?

I'm wondering if I should ask for my money back? I mean, personally, I can clearly see that the BW picture I was editing is bluer on Monitor #1's right compared to Monitor #2's left. (And again, the measurements don't indicate that--wtf? I suppose that could be explained because I calibrated from center, and maybe the end result is a colder monitor #1?)

Which displays are these? If they don't feature screen uniformity correction, and even many mid-high end displays do not, then that could well be what you're seeing, especially if they use CCFL backlighting, those tended to have more variance compared to LED. Otherwise I've only seen what you're describing outside of IPS panels.

Kolor-Pikker wrote in post #17224623
Which displays are these? If they don't feature screen uniformity correction, and even many mid-high end displays do not, then that could well be what you're seeing, especially if they use CCFL backlighting, those tended to have more variance compared to LED. Otherwise I've only seen what you're describing outside of IPS panels.

i was trying to avoid giving away the model, but these have GB-LED backlights, and employ AH-IPS which I understand to be rather high-end. and no, i don't see any uniformity correction. these are about 1yr old.

if one monitor showed these properties i'd think i clearly have one dud, but both like this?

these monitors are advertised to have some of the best color accuracy out there, but i can't see how they could be accurate if one side of the screen is bluer than the other, and if the same girl's face displayed at the same time on both monitors looks different.

now, that said, i do think that it's possible the previous owner never noticed, especially if he never works with black and white images. i was looking at some color images and it's much harder to see--i could only see the difference because i knew what to look for. but i doubt i'd ever have noticed if i didn't work first with a bw image.

I can't claim to do the same experiment as you as I only have one high-end display hooked up to an iMac, but it is also GB-R LED and 99% Adobe, and I do see something peculiar when I'm looking at the screen from an angle with a B&W image opened fullscreen - one side of the screen gradually appears to turn cooler than the other.

I would never notice this since the high-end screen is my main display and I only have miscellaneous stuff happening on the Mac's screen, but if I had two such screens next to each other I would probably be looking at at least one of them from an off-angle.

How are the displays positioned? did you try looking from different angles? One minor con of modern IPS displays is that they have dropped polarizing filters from the formula, resulting in slightly more IPS glow, which this could be related to.

Kolor-Pikker wrote in post #17224645
I can't claim to do the same experiment as you as I only have one high-end display hooked up to an iMac, but it is also GB-R LED and 99% Adobe, and I do see something peculiar when I'm looking at the screen from an angle with a B&W image opened fullscreen - one side of the screen gradually appears to turn cooler than the other.

I would never notice this since the high-end screen is my main display and I only have miscellaneous stuff happening on the Mac's screen, but if I had two such screens next to each other I would probably be looking at at least one of them from an off-angle.

How are the displays positioned? did you try looking from different angles? One minor con of modern IPS displays is that they have dropped polarizing filters from the formula, resulting in slightly more IPS glow, which this could be related to.

yes... i did notice that the temperature appears to change depending on angle of view. however, during examination i made damn sure i looked dead on when comparing different regions. I've stared at this thing so long i think my eyes are starting to bleed. but i am pretty sure that it's not my eyes or the viewing angle at this point. what i see within one single display does seem to be correlated by the colorimeter's temperature measurements.

and as you alluded, if i had just one display i might never have noticed. this thing just screamed at me because i happen to drag a picture across the screens so that it was split between the two, and it was super obvious that the whites were different colors.

Set up both of your displays side-by-side so you can photograph them in the same image. Set the camera up so that the long axis of the lens is perpendicular to the displays. Set up each display so that it is displaying a vertical black-to-white gradient (make one in photoshop and duplicate it and put one on each display). This way you can see what is going on across the display across the range of tones. Do neutrals render neutral? Slide a piece of black or neutral dark paper or cardboard between the two displays so they are not casting light on each other. Shoot the displays in the same image in a darkened room with a fixed white balance (set the camera to 6500°K for example). Expose so the entire gradient is captured. At least this will permit you to compare the displays simultaneously, without your eyes and brain confounding the comparison as you look from one display to the other.

Can you see the differences you describe in the image you shot?

Does your calibration/profiling software give you a delta-E report or similar measure of the quality of each profile it creates?

What happens if you move your iOne over to one side of the display and recalibrate?

I sounds like the displays require manual configuration of the white point and the contrast - that is, the profiling takes place on your video card and not in the hardware LUT. what happens if you set all of the hardware OSD settings on both displays identically and then profile?

kirk

kirkt wrote in post #17225291
Set up both of your displays side-by-side so you can photograph them in the same image. Set the camera up so that the long axis of the lens is perpendicular to the displays. Set up each display so that it is displaying a vertical black-to-white gradient (make one in photoshop and duplicate it and put one on each display). This way you can see what is going on across the display across the range of tones. Do neutrals render neutral? Slide a piece of black or neutral dark paper or cardboard between the two displays so they are not casting light on each other. Shoot the displays in the same image in a darkened room with a fixed white balance (set the camera to 6500°K for example). Expose so the entire gradient is captured. At least this will permit you to compare the displays simultaneously, without your eyes and brain confounding the comparison as you look from one display to the other.

Can you see the differences you describe in the image you shot?

Does your calibration/profiling software give you a delta-E report or similar measure of the quality of each profile it creates?

What happens if you move your iOne over to one side of the display and recalibrate?

I sounds like the displays require manual configuration of the white point and the contrast - that is, the profiling takes place on your video card and not in the hardware LUT. what happens if you set all of the hardware OSD settings on both displays identically and then profile?

kirk

hi kirk,

i agree with you that my eyes may be confounding the results. your methodology is probably as good as any could be for subjective testing.

"Does your calibration/profiling software give you a delta-E report or similar measure of the quality of each profile it creates?"
--it does give a side-by-side quick color comparison at the end, but no real data

"I sounds like the displays require manual configuration of the white point and the contrast - that is, the profiling takes place on your video card and not in the hardware LUT. what happens if you set all of the hardware OSD settings on both displays identically and then profile?"
--in this case i'm not as concerned about one monitor being overall different from each other, because i assume this can be calibrated. what cannot be calibrated is unevenness of colors across the screen, as you can't calibrate one area of the screen vs a different area.

again, i think your methodology is the best you can do for visualizing the problem. but do you really think it's necessary if i already used an instrument to produce actual measurements? i mean, i've done this in a semi-blind fashion where i moved an image of a person's white face around on the screens and noted where i thought it changed cooler or warmer, without looking at the numbers. then when i check the numbers, sure enough, they match what i see.

...i was hoping that someone could comment whether the temperature differences are to be expected for a monitor that retailed for $900-1000 last year, claiming top-of-class color reproduction.

(one monitor has almost a 500deg difference between top and bottom. that to me is huge. i spend 10min sometimes in LR deciding between a temperature difference of 50deg. 500deg to me is big enough to change the appearance of an image profoundly. i just don't get it--there are 2 monitors... can BOTH be broken?)

Did you do a search on the inter webs to see if this is a chronic problem with your model and make of display? How "used" were these and did the previous owner report or disclose these problems? Have you contacted the previous owner to see if they had these problems? It may it explain why the previous owner sold them.

kirk

I recommend you take a look at some of the reviews on TFT Central. You might even find your monitor there.

They do uniformity luminance testing on almost all the reviewed monitors and white point uniformity on the high-end ones.

Here is a link to the uniformity info for the Dell U3014:
http://www.tftcentral.​co.uk/reviews/dell_u30​14.htm

Your monitor #1 shows a max. difference to the middle of about 2%, which I suspect is pretty typical unless you're spending big bucks or the monitor has uniformity adjustment.

Your monitor #2 is a little greater at just under 5%. That might be starting to get not-so-typical.

But as I said, browsing around TFT Central should give you some sense as to how far off the norm your situation may be.

Eyeball2 wrote in post #17227134
I recommend you take a look at some of the reviews on TFT Central. You might even find your monitor there.

They do uniformity luminance testing on almost all the reviewed monitors and white point uniformity on the high-end ones.

Here is a link to the uniformity info for the Dell U3014:
http://www.tftcentral.​co.uk/reviews/dell_u30​14.htm

Your monitor #1 shows a max. difference to the middle of about 2%, which I suspect is pretty typical unless you're spending big bucks or the monitor has uniformity adjustment.

Your monitor #2 is a little greater at just under 5%. That might be starting to get not-so-typical.

But as I said, browsing around TFT Central should give you some sense as to how far off the norm your situation may be.

great site! unfortunately I did not see my model there, but I did check out a few that they executed the white point uniformity check on. interesting. i'm kinda unsure of what they call significantly bad in regards to color uniformity. it does appear that 5% might be getting not so good. but in some cases they were more lenient. seems inconsistent in their opinion of their measured results.

okay... I've contacted the original owner, who btw is really nice and accommodating. I am trying REALLY hard to do the right thing. to me, I've never noticed this issue with my old monitor, but who knows right? but now that I noticed, the color differences are now glaring.

please take a look at these results. the original owner requested I recheck with only using display port. so in these tests I turned off the other monitor and only used display port to connect:

monitor 1
6408 6415 6493
6561 6442 6663
6830 6702 6970
delta from mid
-0.53% -0.42% 0.79%
1.85% 0.00% 3.43%
6.02% 4.04% 8.20%
greatest difference
8.72%
562 kelvin

monitor 2
6323 6223 6156
6660 6425 6402
6898 6712 6700
delta from mid
-1.59% -3.14% -4.19%
3.66% 0.00% -0.36%
7.36% 4.47% 4.28%
greatest difference
11.55%
742 kelvin

what do you guys think??? would you return this? keep in mind, this model was sold advertising color accuracy for media editing. it's not cheap and retailed for ~$1000 for the 27" model at launch, which appears to be a little more than ~1yr ago.

So what do you guys think?