Results: Viewing Angles And Uniformity
The more monitors we test, the more we can see that off-axis viewing performance is dependent not only on pixel structure (IPS, PLS, TN, etc.) but the backlight technology as well. And we can see that the anti-glare layer makes a difference too.
The GB-r-LED backlight seems to return the same off-axis viewing results no matter what product it’s installed in. Brightness falloff is minimal like all the IPS monitors we photograph, but the horizontal plane’s red shift seems endemic to these screens. Vertically, there is no significant color shift and light reduction is fairly small.
Screen Uniformity: Luminance
To measure screen uniformity, zero and 100-percent full-field patterns are used, and nine points are sampled. First, we establish a baseline measurement at the center of each screen. Then the surrounding eight points are measured. Their values get expressed as a percentage of the baseline, either above or below. This number is averaged.
It is important to remember that we only test the review sample each vendor sends us. Other examples of the same monitor can measure differently.
First up is black field uniformity.
Screen uniformity is the only area where the PG2401PT does not excel. Even with uni-comp on, we could still see hotspots in the upper-left and lower-right areas of the screen. Given the small improvement that feature makes, we'd leave it off and avoid the 44-percent contrast reduction.
Here’s the white field measurement:
Again, there seems to be little benefit from using compensation. You'd have a difficult time registering a 7.57-percent error, so there isn’t much point in reducing contrast just to get the uniformity to 1.98 percent. Either way, the screen looks great to our eyes.
Screen Uniformity: Color
To measure color uniformity, we display an 80-percent white field and measure the Delta E error of the same nine points on the screen. Then we simply subtract the lowest value from the highest to arrive at the result. A smaller number means a display is more uniform. Any value below three means a variation that is invisible to the naked eye.
Color uniformity is also boosted by uni-comp. But even when it’s off, we can’t see any problems. Our final conclusion is clear: disable uniformity compensation to maximize contrast. The screen looks fine without it. The black field result isn’t great, but unless you’re working with a lot of very dark content, you won’t notice the hotspots during actual use.
mixed with the convenience for manufacturers of making mostly
1080 screens. When I hunted for a 2560x1600 screen last year,
I was shocked at the prices, because the same thing has happened
at 2560, ie. the market has narrowed in on 1440 height instead of 1600,
so the latter are now expensive (assuming one can find them at all),
eg. the Iiyama XB3070WQS-B1 is about 700 UKP, and the HP Z30i
is more than 1000 UKP.
At the least one positive from all this is that good 1200-height IPS
panels are now much more affordable. My first 1920x1200 IPS was
an HP LP2475W which cost about 450 UKP, but today the Dell U2412M
costs less than half that much (is the Dell better? Well, yes & no,
different feature set, etc., but the screen is nice).
I gave up on finding an affordable IPS 2560x1600, and meanwhile it
was obvious review sites had settled on 1440 height anyway (a few
years ago many sites were still testing wtih 1600 screens, but not
now), so I bought a Dell U2713HM instead which works pretty well,
except for its irritating resolution limitation over HDMI (watchout for
that if you buy a new screen, some models only support their max
res via DVI or DP - the Dell I bought can't do more than 1080 via HDMI).