A chance to talk to FlatpanelsHD's reviewers.
By knutinh
I am having slightly different results when calibrating this screen.

Using Spyder 3 Express with DispCalGui, connecting via Radeon 5570 using dual-link DVI. Letting the screen settle for an hour or so. Setting for 6500K (Daylight), native black/white point, gamma of 2.2, quality set to 'high' (calibration takes about 60 minutes). When doing the calibration, I end up at:
Code: Select all
                 From the review  My calibration
Black level =    0.23             0.38 [cd/m^2]
White level =    225              242.78 [cd/m^2]
Aprox. gamma =   1.92             1.80
Contrast ratio = 978:1            642:1
White chromaticity coordinates    
                 ######           0.2815
                 ######           0.3378
White Correlated Color Temperature (DE 2K to locus)
                                  8186K (20.2)                                
White Correlated Daylight Temperature (DE 2K to locus)
                                  8157K (18.9)
White Visual Color Temperature (DE 2K to locus)
                                  6787K (19.8)
White Visual Daylight Temperature (DE 2K to locus)
                                  6904K (18.4)
I then use DispCalGui to calibrate display controls. As I have chosen native WP/BP, I chose Brightness/Contrast like the reviewer did. However, I end up at very different R/G/B settings, having to boost the red channel a lot more than in the review:
Code: Select all
	          From the review  My calibration
Brightness:	  22               22
Contrast:	    50               50
RGB:	Manually
• R:	         88               100
• G:	         84               81
• B:	         89               83
Calibrated/profiled results:
Code: Select all
                 From the review  My calibration
Black level =    0.12             0.25 [cd/m^2]
White level =    106              116.59 [cd/m^2]
Aprox. gamma =   2.2 (?)          2.18
Contrast ratio = 883:1            472:1
White chromaticity coordinates    
                 ######           0.3123
                 ######           0.3290
White Correlated Color Temperature (DE 2K to locus)
                                 6524K (4.9)
White Correlated Daylight Temperature (DE 2K to locus)
                                 6524K (0.3)
White Visual Color Temperature (DE 2K to locus)
                                 6348K (4.7)
White Visual Daylight Temperature (DE 2K to locus)
                                 6513K (0.3)
I ran tests several times and got only minor variation.

So which should I depend on? Clearly, my calibration wants a lot warmer white-point than the reviewers.

I am also curious about the wide-gamut, and what it really means. Does it mean that my calibrator is useless?

By sarangiman
I have a question, especially to the original author.

When using this monitor in the preset AdobeRGB or sRGB modes, do you set your monitor profile in your operating system to 'AdobeRGB' or 'sRGB', respectively? There seem to be varying opinions all over the internet, & Dell Technical Support is useless (3 people I've spoken to have no idea what I'm talking about).

I understand that these modes limit the gamut of the monitor to the respective device independent spaces, but I wonder if that also means that the monitor response in those modes can be accurately described by the very device-independent profiles themselves. I know in general it's heresy to apply a device independent profile to a, um, device, but if Dell manufactured the monitor/software such that when using it in, say AdobeRGB mode, the monitor's characteristics can be described by the AdobeRGB profile, then one could forego profiling the monitor and just apply the AdobeRGB profile. Though profiling the monitor in either of these modes would still be better!

Last edited by sarangiman on 28 Jan 2012, 20:09, edited 1 time in total.
By Micha

I hope the thread isn't to old to get an answer. ;)

Some days before I bought a u2711 and I would like to use it for image editing and CAD. Two things makes me not happy. First if I look at a fullscreen black image than I see at the right upper side a glow - is this normal by this screen?
Second problem - a white screen doesn't look homogeneous colored, the left side looks cold and the right side warm. I use my blue eye calibration device and measured 5700K and 5400K. So, an image show at the left looks cold and at the right warm. That's a big problem for me.

Now my question - should the u2711 doesn't show this problems or can't I expect to much from this TFT at this price?

I would be happy about any feedback that helps me for my decision for or against the TFT. Money back or change the monitor?


PS: Often people ask for the crystal coating effect - for me it's ok, the screen looks like a little bit dusty, but after a while I forget to see it.
By sarangiman
Hi Micha,

Yes I typically see backlight leakage on many monitors; the magnitude, of course, varies. I haven't found it to be too distracting on my Dell U2711.

What is more distracting to me is exactly what you mention: the magenta-green color gradient obviously noticeable on a blank white screen. I've measured a deltaE of as much as 7 across the screen. I've also noticed a variance of greater than 20% in brightness across the screen (i.e. certain areas of the screen measure 120 cd/m^2 while other areas measure 95 cd/m^2). This sort of variance is pretty displeasing when a discerning photographer may be attempting to calibrate to a certain white point & luminance for print-matching.

I don't know how this variance compares to other large monitors out there (I've certainly seen less variance in smaller monitors), but one can deal with this problem by:

(1) swapping out monitors with Dell until you get a satisfactory unit
(2) profiling the portion of the monitor most used for critical work (probably the center) & accept the color/brightness inaccuracy in other portions.

I don't really know if it makes *that* much of a difference in the end for prints. Yes it's not ideal & I expected better. Don't know what else to say!
By Micha
I returned the u2711 and now I use a NEC PA271. This device use the same panel like at the u2711, but NEC integrated a color comp feature, that compress the strongest color/brightness shifts, but the contrast is lower. I'm not complete happy with the screen, I expected more, but I see no alternative and so I will stay with it. I like the large pixel space.
It looks like this kind of large panels need some more years of development.