HP z27x Review
by Chris Heinonen on December 2, 2014 4:00 PM ESTFor calibrating the HP z27x, we use CalMAN software from SpectraCal. Measurements are made with an i1Pro and a Klein K-10A using APL 50% test patterns. For pre-calibration measurements, I used the sRGB mode on the HP z27x and set the brightness to 200 cd/m2. Our targets are 200 cd/m2 with a Power 2.2 gamma and 80 cd/m2 with the sRGB gamma. We target the sRGB color gamut for these tests.
Pre-calibration the grayscale has a slight blue tint to it. The average color temperature is over 7000K, which corresponds to a blue temperature, and the graphs confirm it. The gamma is very good except at the low end, which is due to the HP using an sRGB gamma instead of the Power 2.2 gamma that we target. The dE2000 error levels stay below 3.0 for almost the whole range from 0% to 100% intensity, so it is still good despite these issues.
More impressive are the color error levels. The color checker and saturations are very good, and would be excellent even if this was after a calibration. Nothing creeps over a dE2000 of 3.0 so these are errors you will not notice in moving content. Pre-calibration, the HP is very good.
CalMAN has the ability to directly control the HP z27x, so it performed the calibration in the display LUT and the video card LUT. This provides the most accurate images possible and allows you to correct color errors that cannot be done in the video card LUT alone.
Post-calibration the sRGB numbers are virtually perfect. There are a couple issues in the grayscale but those are actually reading errors and not real errors. If they were actual errors the numbers around them would be higher as well. I ran into this a couple times with the Klein, probably due to my unfamiliarity with it compared to my usual meters. Gamma tracks almost perfectly, and the RGB balances are basically perfect.
Color errors are practically non-existent, with average dE2000 levels below 0.5. For professionals where accuracy matters, the HP z27x delivers that after calibration.
Results are the same when we target 80 cd/m2 and an sRGB gamma curve. You can see a couple of reading errors, but overall the display is virtually perfect. Contrast ratios fall a bit as it corrects 100% white, but there aren’t any major issues in the display.
Pre-calibration the numbers from the HP are good but they get to be reference class after calibration. Anyone using this display is going to calibrate it, because that is their target market, and it offers the ability to be completely dialed in.
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bobbozzo - Tuesday, December 2, 2014 - link
Hi,It wasn't clear to me which is preferred - using (renting?) a Klein K-10A colorimeter and doing the self-calibration, or doing software calibration?
Thanks for the article
cheinonen - Tuesday, December 2, 2014 - link
Doing it inside the monitor is best, as you don't need to worry about the PC LUT being correct, it will just be accurate on any computer hooked up to it.Samus - Tuesday, December 2, 2014 - link
A worthy successor to my Dreamcolor LP2480, moar resolution and USB 3.0!Oubadah - Sunday, December 21, 2014 - link
Plus no A-TW Polarizer and inferior backlight array. This monitor isn't in the same class as the last gen Dreamcolor. Not to mention it's bugs and abysmal quality control. http://www.liftgammagain.com/forum/index.php?threa... I wouldn't touch this monitor with a barge pole at the moment.tyger11 - Tuesday, December 2, 2014 - link
When are we going to see monitors with HDMI 2.0 and DP 1.3?cheinonen - Tuesday, December 2, 2014 - link
Once we have chipsets. The issue with HDMI 2.0 is that all the current HDMI 2.0 chipsets with the full bandwidth don't have HDCP 2.2 as well. The HDCP 2.2 chipsets only use a subset of HDMI 2.0 and so they can't send as much data. Hopefully at CES next month we'll see products announced using new chipsets.wolrah - Wednesday, December 3, 2014 - link
Does HDCP actually matter to PC users? Aside from legitimate playback of Bluray/HD-DVD content what else on a PC ever gave a shit about it? I think iTunes did at one point, no idea if it still does.I mean there are technically roles a PC can fill for which it matters, but personally even among those I know who have BD-ROM drives in their PCs (a slim number, optical drives altogether are a dying breed) I don't know anyone who actually uses their PC to watch movies from disc. Anyone who uses discs uses a hardware player or more often a console, and anyone who uses a PC just sources from the internet in one way or another.
For TVs HDCP is a big deal, but for a computer monitor I'm finding it hard to care.
cheinonen - Wednesday, December 3, 2014 - link
I don't know that it's a big deal for straight PC usage, but it's also likely to upset people if they buy an HDMI 2.0 monitor, only to discover when they try to hook up their other 4K devices to it that they won't play back a 4K image. Since the chips are expected to be at CES, I don't think we will have to wait too long for them and IMO I'd rather have a display that can do that, without needing MST for a 60Hz refresh rate, than have a monitor today that will be out of date that fast.chaos215bar2 - Wednesday, December 3, 2014 - link
On a Mac, at least, iTunes most certainly still does care about HDCP. Even Netflix manages to check it when using the HTML5 player. HDCP may be silly, but it's still important if you want to watch videos on your computer without the hassle of stripping DRM.DanNeely - Thursday, December 4, 2014 - link
As of about 8 months ago (last time I tried using it) Amazon Instant Video also required HDCP for higher quality streams.