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.
Facebook
Twitter
RSS
47 Comments
View All Comments
SanX - Sunday, December 7, 2014 - link
The author has done absolutely right things. HP indeed does not care even to cherrypick. HPs and Dells became more and more a rebranders of Chinese goods. And actually it is not the China the final reason in bad quality control of everything but WE THE BRAINDEAD PEOPLE and of course our croocky american sales/middlemen who exploit this vulnerability of average technically illiterate Joe and are just interested to drop more larger margin shiny crap on the heads of dumb public, on our heads.DanNeely - Tuesday, December 2, 2014 - link
It might've been the 1st time it crossed your desk; but NEC's offered in monitor calibration since (at least) the the Multysync 3090 (released around 2008). I'm not sure how it compares with HP's offering; but they've got something called NaViSet to allow centralized admin of display settings. Lastly, IIRC their internal calibration does have some ability to adjust for uneven backlighting (presumably at the cost of some overall contrast).http://www.necdisplay.com/support-and-services/nav...
cheinonen - Wednesday, December 3, 2014 - link
I've used and reviewed the NEC PA series, and while they offer an internal LUT with calibration options, it has to be done through the SpectraView II software. The HP allows you to do it entirely inside the display without a PC at all, making it easier to do a large number of them. The NEC PA series also lacks the Ethernet control. The uniformity on the NECs is top notch.baii9 - Tuesday, December 2, 2014 - link
Wide gamut -> GB-r LED -> uniformity issue, why am I not surprised.Here is when good warranty kick in, panel lottery.
Doomtomb - Tuesday, December 2, 2014 - link
This monitor came out in 2014? This looks like something that would've come out in 2009. The bezel is huge. The body is thick. The resolution is nothing special. I don't care if it has features, and the color gamut. Seriously, this is the mind of the average consumer.D. Lister - Tuesday, December 2, 2014 - link
This product isn't targeted at the average consumer.DanNeely - Wednesday, December 3, 2014 - link
Although one of the reasons why pro-grade monitors tend to be significantly thicker than consumer ones is to put an array of evenly spaced backlights behind the panel instead of just a few on one or more edges using mirrors to bounce it around; because the former results in more even illumination.Something that clearly didn't happen with this monitor; and since AT has proven willing to hold reviews if they see unexpectedly bad results and the vendor says "looks like something broke, let us send you a replacement to test" or "we didn't test that case and need to write a new firmware to fix the problem" I can only assume that HP considers the level of backlight variation Chris saw in this model acceptable.
kyuu - Thursday, December 4, 2014 - link
Based on Chris's own statement in these comments, your assumption would be wrong. It seems that Chris didn't inform HP or offer them the chance to send a replacement in order to avoid the appearance of receiving a "cherry picked" sample.... Seems kinda silly to me. Unless Chris purchased the review unit himself, HP already had the chance to submit a cherry picked sample. Giving them the chance to fix what may very well be damage incurred during shipping does not somehow break reviewer ethics.
baii9 - Wednesday, December 3, 2014 - link
average consumer don't drop 1.4k on a 27" monitor.jann5s - Wednesday, December 3, 2014 - link
The ASUS MX229Q is using more power at minimum then at maximum, I guess there is a booboo in the database (LCD Power Draw figure)