Dell UltraSharp U2711: Quality has a Price
by Jarred Walton on January 22, 2010 2:00 AM EST- Posted in
- Displays
Dell U2711 Color Quality
We'll start with a look at the color quality of the U2711, broken down into two areas: Color gamut and color accuracy (i.e. Delta E). We'll start by explaining the former. Color gamut refers to the ability for a display to represent all of the colors in a defined selection of colors. In this case, we use the Adobe RGB standard to define the base gamut, and we measure the percentage of that standard that a display is able to cover - higher being better.
Delta E is the difference between a requested color and the color that actually appears on the display, with lower being better - i.e. the displayed color doesn't have a large delta relative to what was requested. If a display has perfect color accuracy, Delta E will be 0.0; in practice, anything less than 1.0 is nearly perfect and no one will notice the difference. A Delta E of 2.0 or less is the desired result after calibration, meaning no one color measures higher than 2.0 on our standard 24 color palette. Such a result would be fit for use in any professional imaging environment. Finally, while Delta E of around 4.0 is visible to the naked eye, it's really a question of reference points; if you don't have something better nearby and you're not going to print or view content on other media, a result where all colors measure 4.0 or less is very good.
So how does the U2711 do in these areas? First let's look at the charts, and then we'll discuss what they mean. We used the Graphics and Adobe RGB setting on the U2711, with brightness set at 36% (~200nits) and contrast at the default 50%.
The U2711 scores extremely well in color gamut, and it achieves the 96% of Adobe RGB that Dell claims in their literature (not that most users would really notice the difference between any of the displays rated 90% to 105% - at least not after you eliminate the TN panels). Color accuracy on the other hand is a bit of a mixed bag. Dell ships a paper with test results showing the color calibration of each individual U2711, with the claim that the displays will have an average Delta E of less than 5.0 without any end-user calibration (when using the sRGB and Adobe RGB settings). Dell uses Minolta Color Analyzer CA210 and 32 test colors while we test with ColorEyes Display Pro and Monaco Optix XR Pro and 24 test colors, but our Monaco results confirm their claim. We're not sure why, but we continue to get better results using Optix XR Pro than with ColorEyes Display Pro.
As far as Optix is concerned, the U2711 achieves the rated Delta E of < 5.0 at just 2.24 without calibration, which is an excellent result. In fact the U2711 has no colors in the standard Gretag Macbeth 24 color palette score higher than 5.0 (and only reddish-pink scores a 5.0 measurement). The only LCD we've tested that did better is Dell's own 2408WFP (which also, interestingly enough, had an Adobe RGB color gamut of 105%). ColorEyes also gives an average Delta E of less than 5.0, but at 4.78 the score isn't nearly as remarkable, with nine color measurements well above 5.0. The uncalibrated (Monaco) results put the U2711 ahead of the HP LP3065, Dell 2707WFP, Samsung 245T, and LaCie 324 - and just about every other LCD we've tested.
Switch to the calibrated results and the U2711 doesn't impress quite as much relative to the competition. Monaco gives the U2711 an average Delta E of 1.06, which is great, but there are two results above 3.0 (the worst is reddish-pink again, this time at 4.31) compared to displays like the HP LP3065 where the highest measured Delta E is just 1.68. Dell's own 2707WFP, a three-year-old offering, also delivered a similar average Delta E but with only two colors above 2.0 (and still under 3.0). For a better LCD (i.e. not a TN panel), the results are really only slightly above average. It is possible different calibration software would achieve a better end result, but really we're talking about a "problem" that only the most demanding users are likely to ever notice.
Color Consistency
We added another test to try and measure the panel consistency across the entire surface. We measure Delta E at the center of the display, but what happens on the edges? To test this, we used the same profile generated in our best Delta E test result and measured Delta E again at the four corners. Most of the scores are similar, with a slight increase in average Delta E relative to the center measurement. The bottom-left corner is nearly identical to the center measurement, the top-left and bottom-right are a bit worse, and the top-right corner gets the overall worst result. While on the one hand we could say that the Delta E on the top-right is twice that of the center measurement, it's not a case of being "twice as bad". In fact, the color consistency is very good, and we didn't notice any "hot spots" are areas where the colors were clearly off relative to the rest of the LCD.
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Griswold - Sunday, January 24, 2010 - link
Go buy TN if you want to play games and are unaware of the _real_ benefits of IPS and PVA.darklight0tr - Friday, January 22, 2010 - link
Ugh...this is step backwards. 16:9 and an insane pixel pitch that is too small for most users.I owned the 2707WFP and currently use the 2709W because of the 16:10 aspect and high pixel pitch (1920x1200, 0.303). Because my eyesight isn't perfect it is a great LCD monitor for me, plus unlike the 28" TN based displays you could get a good quality S-PVA display with either one.
Now Dell has killed that option with this introduction. They took a step forward with the IPS display, but switching to a low pixel pitch 16:9 display sucks. I've used the 3007WFP and that pixel pitch would drive me nuts for normal use, most things are just too small despite the nice increase in real estate. Plus, doesn't this LCD strongly overlap with the existing 3008WFP?
Luckily I don't play on purchasing a new display anytime soon.
MadMan007 - Friday, January 22, 2010 - link
Also luckily for you this isn't meant as a direct replacement for the 27" monitors you have I don't think. It's a professional monitor with fancy color capabilities and electronics that aren't needed for general home and office use.darklight0tr - Saturday, January 23, 2010 - link
Given the fact that it shares the model number scheme with the previous monitors it is hard to know right now if it is a replacement for the 2709W. I guess we will know when the 2709W is phased out. If it gets a similar replacement (1920x1200 16:10) my previous comment is null and void.mczak - Friday, January 22, 2010 - link
"Note also that the HDMI connection uses the 1.3 standard, so it won't support resolutions above 2048x1152 (a 16:9 resolution)."That kinda sucks. Note that HDMI 1.3 definitely DOES support 2560x1600.
However, seems to be a useless paper spec. Some devices implement other features of hdmi 1.3 (like 30 bit color) however as far as I can tell there are neither monitors nor graphic cards which could output higher resolutions over (single-link) hdmi thanks to the possible higher link bandwidth. Even HD5xxx series graphic cards seem to be limited to 1920x1200, and for the monitors it's often impossible to even figure out as they just list "hdmi 1.3" but they don't tell you they actually don't support the higher bandwidth modes... And that spec is getting old already...
JarredWalton - Friday, January 22, 2010 - link
It could be my laptop that didn't support the appropriate resolution over HDMI, then.... let me test with the M6500 and see if that will do more than 2048x1152 on HDMI. I know that at least one laptop wouldn't allow anything higher. BIAB....Oops... the Dell M6500 doesn't have an HDMI port; just VGA and DisplayPort. If I could find my DVI to HDMI adapter I could try it on a different GPU; as it stands, all I know is that on the test laptop, HDMI limited the maximum resolution. (FWIW, I have a Dell Studio XPS where the DisplayPort tried to output 2560x1440 but the GPU apparently wasn't designed to do that. That same Studio XPS didn't give an option to try 2560x1440 on HDMI.)
Gnyff - Thursday, August 5, 2010 - link
I own the U2711 - and love it :-)I agree with mczak: The vendors are very bad at specifying what their HDMI does - even if they say 1.3 I'm not 100% sure they support the high bandwidth...
I'm very interested in real life experience with 2560*1440 over HDMI. I'm not certain that the U2711 actually supports it - and I've NEVER seen any of the notebook manufacturers specify maximum resolution over HDMI. But there's nothing in the specs preventing a well designed HDMI 1.3 notebook and screen to run at 2560*1440! Actually this /should/ be a certain thing if they both specify HDMI 1.3 (and at least Dell does!)...
However, the only safe for now bet seems to be Display Port - but they are mainly on the brand new notebooks and I HATE the glossy screens they usually come with. HP 8740W and Dell 6500 seems to be exceptions - but they are currently a bit outside the price range I was hoping for ;-)
Lord 666 - Friday, January 22, 2010 - link
If you are concerned about cost as I am, what about reviewing the 24" version or comparing along side? Don't understand why the review focused on a very large monitor that is a niche product.Mr Perfect - Friday, January 22, 2010 - link
Here's a professionally done review of the U2410, if that's the one you're looking for.http://www.tftcentral.co.uk/reviews/dell_u2410.htm">http://www.tftcentral.co.uk/reviews/dell_u2410.htm
JarredWalton - Friday, January 22, 2010 - link
Because it was offered as a review unit. LOL. I've been doing a lot of mobile reviews and it's hard to get in displays and laptop coverage from one person. This is why we have that call for writers that went out; I'm hopeful that I can turn all display reviews over to someone else and focus on just one area (more or less).