HP z27x Review

For 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.