Page 1:HP Z27x DreamColor Professional Display Review
Page 2:Packaging, Physical Layout And Accessories
Page 3:OSD Setup And Calibration Of The HP Z27x
Page 4:Results: Brightness And Contrast
Page 5:Results: Grayscale Tracking And Gamma Response
Page 6:Results: Color Gamut Accuracy
Page 7:Results: Viewing Angles, Uniformity, Pixel Response And Input Lag
Page 8:HP Z27x DreamColor Display, Accuracy And Flexibility
OSD Setup And Calibration Of The HP Z27x
The Z27x can’t be calibrated using the OSD, but there are many options to configure. Most features are included to address specific user requests. We’ll cover the calibration procedures below. First, though, let’s check out the monitor’s other features.
Pressing any key brings up a quick menu. Once the Z27x is set up, you rarely need to venture past this point.
Selecting Luminance brings up a slider that tracks pretty closely to the actual brightness value. We found it to be off by about 5 cd/m2.
There are two pages of signal and monitor information available. Most visual effects artists work in multiple colorspaces, so it’s important to know how the display is set. If you color correct a project using the wrong settings, a lot of time can be wasted.
Note that in addition to the serial number, you also get a firmware version. This really helps when tracking support issues across a large group of displays.
The second screen has detailed signal info, including scan rates and color formats.
Here’s the main menu tree. You can change the color space without going in this far if you want, but if you make changes from the main OSD, you get a few extra options.
There are seven color modes corresponding to broadcast industry standards, plus a Native mode. That’s where you’ll find extra light output if you need it, as the other modes are limited to 250 cd/m2. You can also back up to a previous calibration or reset to the factory one. If you select Color Space Information, this screen pops up:
This is a quick and easy way to see all image parameters in one place. You can review the color coordinates in either xy or u’v’ format, and you get the white point and gamma specs. When calibrating the Z27x, any specs can be assigned to any color mode. For example, if you wanted a 2.4 gamma in Rec.709 instead of 2.2, you’d only need to specify that when you calibrate.
Here are some options you won’t find on many computer monitors. Video levels are different from PC levels, and the Z27x lets you specify them on the fly. Let’s say you’re mastering a Blu-ray transfer. You’d have to view the signal with video levels to set the black and white thresholds correctly.
Overscan imitates the typical five-percent zoom-in many HDTVs do when not set to a pixel-mapped aspect ratio. If you’re composing an image, it helps to know what content will be cut off and this option shows that.
Showing only the blue channel is a way to easily see compression and encoding errors when mastering content.
Selecting Advanced accesses three more features.
Overdrive is found on most computer monitors today. It simply attempts to reduce motion blur by bumping up the pixel clock.
Deinterlacers are found on all progressive-scan displays. Most computer monitors include a rudimentary video processor to accomplish the task, but the Z27x boasts a more advanced solution. To correctly process film-based video, you need a proper implementation of 3:2 pull-down, which HP provides. If you’re working on film-to-video transfer, this feature is invaluable. You can turn both that and Cadence Detection on and off to check for content encoding errors.
PIP options are pretty typical, though the Z27x adds the ability to use video levels and/or overscan for one source only. That makes it easy to compare images to one another.
Digital Cinema Options are grayed out unless a signal of 4096x2160 or 2048x1080 is input. Those resolutions are known as DCI containers. Once you do this, you can crop the image to a 1.85:1 or 2.39:1 aspect ratio, which corresponds to the two most common film formats in use today.
The Management sub-menu has many options that help both users and administrators manage the display. Most of them have an enable/disable switch. DisplayPort compatibility can be set to either version 1.1 or 1.2.
The most important option available is Manage Internal Processor. Enabling this turns on the Z27x’s internal calibration engine. It also allows firmware updates and remote management.
Remote Management Services allow administrators to control multiple Z27x displays via IP, provided you connect them to your network through the Ethernet jack. HP provides a downloadable API that has a large list of management features. When active, administrators can check the calibration status, display hours, and many other statistics simply by polling the displays remotely.
The OSD can be positioned anywhere on-screen. We moved it to the lower-right, leaving the center of the screen free for test patterns. The timeout can be up to 30 seconds.
The bezel buttons can be programmed for different monitor functions, saving you a trip to the OSD. It’s handy when you want to quickly switch aspect ratios or engage overscan, for example.
When working in a dark office, the bezel lighting can make a significant impact on image perception. By default, the buttons fade to black when the OSD disappears. But if you prefer, they can be always white or red. You can also have them switch automatically to red when the luminance is set below 70 cd/m2.
Lastly, the Z27x has a portrait mode that automatically flips the image. This doesn’t extend to the OSD though, necessitating a manual flip in the settings.
Calibration options for the Z27x are somewhat different than the norm. There is no way to adjust image parameters using the OSD, aside from color mode selection and luminance level. The factory calibration is pretty accurate according to our tests, but HP recommends re-adjusting every 1000 hours. To that end, there is an internal engine that can automatically calibrate using a supported meter.
The least-expensive solution is HP’s DreamColor Calibrator. It’s an i1Display-based colorimeter made by X-Rite and costs an additional £180. If you want to use a more precise instrument, the Z27x supports five different Photo Research spectroradiometers, along with the Minolta CA-210 and Klein K10-A units. They plug right into one of the USB 2.0 ports and can calibrate without any connection to a computer.
We obtained the DreamColor solution from HP and calibrated four different color space modes. When you plug in, a menu pops up where you can enter gamma, white point, luminance, and color gamut choices. These can be saved to any of six memories. Then you place the calibrator on the screen and the Z27x does the rest. It took us about one minute per color mode, while a spectro can take up to 40 minutes.
As you’ll see in our tests, the DreamColor instrument didn’t really improve upon the factory setup. We feel that, to realize the Z27x’s full potential, you’d need to use an i1Pro at minimum. Unfortunately, the only way to use that particular instrument is with the latest version of CalMAN. It has the appropriate software hooks to calibrate the monitor and write to its internal look-up table.
- HP Z27x DreamColor Professional Display Review
- Packaging, Physical Layout And Accessories
- OSD Setup And Calibration Of The HP Z27x
- Results: Brightness And Contrast
- Results: Grayscale Tracking And Gamma Response
- Results: Color Gamut Accuracy
- Results: Viewing Angles, Uniformity, Pixel Response And Input Lag
- HP Z27x DreamColor Display, Accuracy And Flexibility