HP's Latest Is an Impressive Color-Critical IPS Display Aiming for the Sweet Spot Between Performance and Affordability

Over the past few years, HP DreamColor monitors have become the default choice for many post-production facilities that do color-critical work. According to HP, 80 percent of the Academy Award nominees for visual effects since 2011 have used them. You’ll find them in many of the top animation studios. And the DreamColor technology even won an Academy Award for itself (back in 2015) from the Scientific and Technical branch of the Academy.

But, as they say in Hollywood, “You’re only as good as your last picture.” With the center of gravity having shifted to 4K, HP has been under pressure to offer a DCI 4K version of its DreamColor monitor. That monitor would need to have the same kind of color accuracy and post-production features that made the previous models so well-regarded throughout the industry.

Enter the HP DreamColor Z31x Studio Display. It’s a 31.1-inch 4K monitor with a native 4096 x 2160 resolution at 60Hz. It features a true 10-bit IPS panel that covers 99 percent of the DCI-P3 color gamut (or 80 percent of BT.2020). The display has a typical 1500:1 contrast ratio, which is unusual for a high-quality IPS panel with such wide viewing angles. And there’s a built-in colorimeter that can automatically calibrate the monitor, even when it’s unattended.

This latest DreamColor has additional workflow features that are targeted specifically for post-production. There’s an assortment of masks and markers to help you deal with various aspect ratios and safe action areas. (If you need something more specific, you can create your own markers with simple XML coding.) There’s a True 2K upscaling option to help you deal with pixel artifacts when viewing HD content on a 4K display. And an integrated KVM switch can help you meet MPAA security guidelines for a fully isolated production network.

HP DreamColor Z31x

The HP DreamColor Z31x is a key component of a color-critical workstation set-up.

Bumping the Limits

Why doesn’t the Z31x cover 100 percent of DCI-P3, rather than the specified 99 percent? As you might expect, that last one percent is incredibly difficult to cover, unless you’re willing to pay a much higher price for your color-critical monitor. In this case, the errors are in the green and red primaries, though the error rate is under a single delta-E point. With that small an error rate, the human eye wouldn’t be able to see the difference. The monitor technically covers 99 percent, but in perceptual terms, it might as well be 100 percent.

While the color gamut is only marginally improved over the first-generation Z27x, the contrast ratio for the Z31x is significantly improved. The Z31x is rated for a typical contrast ratio of 1500:1, and HP guarantees that the panel will have a minimum contrast ratio of 1200:1. That’s a big deal. Most manufacturers won’t set a minimum, so you’re stuck with whatever variance occurs within the manufacturing process. HP has instructed the panel manufacturer to test and reject any panel that doesn’t meet the minimum requirement. That should be a standard guarantee for any monitor, but it’s actually highly unusual. When the monitor specifications show a “typical” contrast ratio with no minimum listed, you’re betting that the panel manufacturer doesn’t have off days.

HP DreamColor Z31x ports

Various ports on the underside of the HP DreamColor Z31x.

So who makes the panel for the Z31x? There’s an interesting background story on this, because the current crop of IPS panels may have been compromised to make them more widely available. According to Greg Staten, who is HP’s DreamColor product manager, HP couldn’t find a panel with the performance it needed because the panel manufacturers had altered the original IPS design to lower the cost of the panels. “The dynamic color was sacrificed,” Staten explained. “The viewing cone — the true viewable width of the display — was reduced.” And the newer panels have an issue that Staten refers to as black lift. “That’s where as you move your head either up or down, as if you were standing up or, most critically, for someone who is standing off shoulder, you see a different level of gray in the black.”

That last issue wasn’t a problem with the first-generation Z27x, when the IPS panels were manufactured to an earlier, less-compromised standard. So HP approached Panasonic and asked that company to use the original IPS patent as a basis for creating a new, customized panel for the Z31x. HP refers to the panel technology as High Performance IPS, though it may be more accurate to think of it as Classic IPS Plus.

The biggest difference in the Z31x panel over the previous Z27x panel is its ability to render deep and pure blacks. If you’re hoping to find OLED-type blacks in a reasonably priced IPS display, this is as close as you’ll be able to get with the current technologies. When you place a Z31x monitor beside an older Z27x monitor, you’ll see that the blacks are noticeably improved, to the point where you may not want to go back.

Because Panasonic adapted the panel from its earlier IPS technology, the displayed image remains remarkably consistent across its 178-degree viewing range, both horizontally and vertically. If you tend to use your monitor to show content to more than one person at a time, this could be a critical advantage. The fall-off in contrast, color, and brightness is barely noticeable across the angles that would typically involve group viewing. And the anti-glare matte surface on the display will be easier on the eyes when multiple people are viewing the monitor. You’ll see some slight reflection, but it’s diffuse enough that you can ignore it without much effort.

Pick a Color

Regular color calibration is essential for color critical work. For larger facilities, it’s often complicated by having to have multiple displays calibrated to a single source. And for smaller facilities, color calibration is often delayed or never done, because the process is too time consuming or disruptive.

HP DreamColor Z31x colorimeter

The HP DreamColor Z31x has a built-in colorimeter, including a motorized sensor that drops down from the top bezel.

The built-in colorimeter in the Z31x allows the calibration process to occur without human intervention, or even without having a computer attached. The colorimeter is motorized, with a sensor that automatically drops down from the upper bezel. You can set up the calibration on a schedule that you determine, such as midnight every Saturday night. You could have the monitor wake up at 8:00 a.m. each morning and perform a daily calibration at 8:30 a.m., after the panel’s colors have had a chance to stabilize. Or you could run the calibration on demand, if you need to quickly align the monitor.

The Z31x ships with seven factory-calibrated color presets: DCI-P3 D65, BT.709, BT.2020, sRGB D65, sRGB D50, Adobe RGB D65, and Adobe RGB D50. And you can recalibrate any of the factory presets to accommodate your preferences. For example, the sRGB D65 is set to the full luminance level of 250 cd/m2, which is quite bright. You might recalibrate the sRGB D65 preset to a more moderate 100 cd/m2.

The most powerful way to operate the internal calibration system is to control it with your own XML-based instructions. The StudioCal XML code that the Z31x supports is simple and straightforward, and HP provides examples in the user guide and website that you can run as-is or modify.

It’s worth exploring the StudioCal XML feature, because you can use the code to alter more than just the calibration settings. You can name your color presets, specify the color primaries and white point, perform a customized validation pass, and archive your monitor’s calibrated LUTs to a USB flash drive. You can even use an XML script to dump the monitor’s entire configuration to a flash drive, so that the configuration can be duplicated on another Z31x.

Some facilities own expensive colorimeters, spectrophotometers, and spectroradiometers that they use to calibrate their projectors and high-end monitors. The Z31x supports a direct connection to many of these devices, including various models from Klein Instruments, Photo Research, Konica Minolta, X-Rite, and Colorimetry Research. You’ll be able to align the Z31x’s internal colorimeter to your house reference instrument. The Z31x runs a correlation calculation to compare its own calibration with the calibration in the external instrument. It then adjusts its own measurements to take into account any difference in the measurements. That way, all your displays can be calibrated to a single source.

Plays Well with Others

The native resolution in the Z31x matches the full frame DCI 4K standard (4096 × 2160). That’s very close to a 17:9 aspect ratio, which is wider than the 16:9 aspect ratio associated with the SMPTE UHDTV1 4K standard (3840 × 2160). The Z31x provides various fill-to-screen options (proportional and non-proportional) for 3840 × 2160 source input. It also supports DCI masking for 1.85:1 and 2.39:1. When DCI masking is enabled, the source signal is masked to show only the pixels within the chosen aspect ratio.

You’ll find a wide range of industry-standard markers in the Z31x. And you can create your own markers using the supported XML scripting capability. The customized markers can have as many as 16 on-screen lines, with each line having its own color and line width. The lines can be as wide as 10 pixels. The Z31x user guide has marker examples in XML code that you can use as is or modify.

The ability to customize your own markers could be especially useful if you create content for the TV networks, which often have holdout areas for pop-outs, bugs, or promos. If you’re adding subtitles to your video, for example, you wouldn’t want the network to run a graphic on top of your subtitles. Once you have the specifications from the network, you can rope off those areas within the display so that you can see when editing which spaces are reserved for the network.

HP DreamColor Z31x

A sideways-swiveling screen can make collaboration easier

While 4K is coming in fast, most in post-production still deal with HD content on a regular basis. And we’ll likely be viewing 1080p video on our 4K monitors for many years to come. That could be a problem if the 4K monitor doesn’t properly scale up the content. Any monitor or consumer TV can blindly convert HD to 4K, but if it doesn’t scale correctly, the image will be soft. And the scaler may artificially sharpen the video to counteract the softening. This might be fine for causal TV viewing. However, it could be a serious drawback if your job involves evaluating pixel defects or other quality issues as part of your workflow.

Instead of just blowing up the HD video to fit into a 4K frame, the Z31x’s True 2K mode doubles the pixels of the video both vertically and horizontally, so that each pixel becomes exactly four pixels when you view either 2048 x 1080 or 1920 x 1080 video. No video interpolation is applied. With 720p video, each pixel becomes nine pixels. You may not want to view your computer desktop this way, especially with the one-to-nine scaling for 720p. In that case, you may decide to switch on this particular feature only when using the Z31x as an external monitor.

Other options for displaying sub-4K video include a pixel-for-pixel mode. With this mode, lower-resolution video is shown in its native size along with a border to fill out the 4K frame. The Z31x offers a picture-in-picture mode, where one video source is overlaid over another, as well as a 2 x 1 dual split, where one video source is positioned horizontally adjacent to the other. To show full-height side-by-side sources, you’ll want to set the display resolution in your operating system to 2048×2160.

The built-in KVM switch could end up being one of the most important additions to your daily routine. If you’ve had to implement a production network that’s completely isolated from the internet, based on recent security recommendations from the MPAA, you may be using two keyboards, two mice, and two computers just to answer your email while working on your video. The Z31x has a keyboard USB port that includes the same chipset that you would find in a dedicated KVM. If the port sees a specific keystroke combination (Ctrl, Ctrl, Up Arrow), it can switch to another computer network and hand off all USB data to that other computer. The KVM feature can work with any two of the five inputs. And you can use the picture-in-picture or split-screen modes to view both networks at the same time. If you’re rendering a project and want to keep an eye on the rendering process while you check your email, you could strategically position the picture-in-picture so that both tasks are visible at the same time.

A professional-quality KVM switch can cost hundreds of dollars, so having a KVM switch built into the monitor could be a real plus if you need to work on a secure network. Everyone else can just leave the KVM feature in its default off position. That way, you won’t have to worry about accidentally pressing Ctrl, Ctrl, Up Arrow.

HP DreamColor Z31x

Rear view of the HP DreamColor Z31x with accessory mount.

In case you’re wondering, there’s no built-in SDI converter, like the one that you’ll find inside the Sony BVM-X300. In order to keep the price at a more manageable level, HP chose to include an SDI accessory mount rather than an SDI converter, which many potential buyers would rather not have to pay for. The accessory mount is compatible with SDI mini-converters from AJA and Blackmagic Design.

Hands-On Experience

I’ve been using a first-generation Z27x as my main monitor for the past few years, and I was surprised how much better video and photos look on the Z31x. There’s only a small increase in the color gamut between the two models (from 98.8 percent to 99 percent of DCI-P3), but there’s a big jump in the typical contrast range (from 1000:1 to 1500:1). The blacker blacks enrich all the colors — not just black and white content — providing a more satisfying and realistic rendition.

The image quality on the Z31x holds up extremely well when viewed from almost any angle. It’s easy for a manufacturer to quote an impressively wide viewing angle, but all too often, the color and contrast fade quickly as you move off center. That’s not the case with this monitor.

There does seem to be a slight reduction in the response time for the Z31x. Where the original Z27x had a 7ms response time, the Z31x has an 8.5ms response time. Personally I didn’t see any increased lag when viewing fast-moving video on the Z31x versus the Z27x, but it could be an issue if motion discrepancies are critical to your work.

Those response times were measured with the overdrive mode enabled. With overdrive switched on, you can improve the response time and reduce image smearing, but you’ll run into some limitations with this monitor. For example, the picture-in-picture feature may be disabled for certain input resolutions when the overdrive mode is engaged. According to HP’s datasheet for this monitor, the Z31x has a 20ms response time when overdrive is switched off. The onscreen menus let you enable or disable the overdrive mode.

The calibration process went smoothly, both when I scheduled it for off hours and when I ran it on demand for a quick adjustment. Unfortunately, there’s no provision for interrupting the process once it begins. Keep that in mind if you decide to calibrate the display in the middle of a busy work day. The monitor (and possibly your computer) will be inaccessible for approximately 16 minutes.

HP DreamColor Z31x buttons

Close-up look at the menu-access buttons on the bottom right of the Z31x’s screen.

I did find that the on-screen menus can be considerably slower on the Z31x than on the first-generation Z27x. It’s not just that there are more menus and settings than before, which you would expect given the extra features and support for additional standards. The menus themselves seem to update more slowly. I saw the biggest difference when I manually changed the luminance level. For example, when I lowered the luminance level from 100 cd/m2 to 48 cd/m2 using the bezel-mounted function buttons, it took 15 seconds to traverse that range on the Z31x compared with just 3 seconds on the Z27x. Given that the internal processor is likely faster in the Z31x than the first-generation Z27x, the slower menus may be an issue that could be corrected later via a firmware update.

Even though the Z31x isn’t designed for home-theater use, it does support HDCP on all its video inputs. I was able to view a Dunkirk 4K UHD disc that was playing through an Oppo UHD-203 disc player. And I was able to view a 4K version of Blade Runner 2049 that was streaming from an Apple TV 4K. Unfortunately, the Z31x doesn’t support HDR in any of its current forms. Though restricted to SDR, the 4K video quality was impressive when combined with the UHD-203 and Apple TV.


It’s an exciting time to be shopping for a 4K display. On the high end, we have some extremely capable 4K monitors, such as the Sony BVM-X300 30-inch 4K OLED monitor and Canon DP-V3010 30-inch 4K IPS monitor. Both can handle 4096 x 2160, but they’re considerably more expensive than the Z31x. Rising up from below, we have a new crop of HDR-compatible 4K monitors that are targeted to gamers. These include the Acer Predator X27 and ASUS ROG Swift PG27UQ. They have fast refresh rates, but these are UHD-resolution monitors with a more limited color gamut. And there are quite a few less-expensive 4K monitors from companies such as Dell, LG, Samsung, and BenQ. They tend to be UHD rather than DCI 4K, and they don’t offer as many relevant features as the Z31x.

HP is hoping to fill that sweet spot for professionals who are willing to pay a premium for a color-critical DCI 4K monitor but would balk at paying too much of a premium to get there. With its high-quality IPS display, automated calibration, XML scripting, and industry-standard masks and markers, the HP DreamColor Z31x Studio Display is likely to become the workhorse DCI 4K monitor for post-production, visual effects, and animation.

HP DreamColor Z31x

The Z31x in the field.