One of the attractive aspects of the EliteBook is its DreamColor display, which provides outstanding color response and calibration capabilities which are suited towards film and video pros. In the second of our multi-part series, we take a look at DreamColor and review some of the tech details behind it.
First, a tiny bit of history regarding HP and DreamColor. The DreamColor moniker actually refers to combination of HP technologies and external color management tools which are geared to create a high level of accuracy in color reproduction in digital workflows. This initially focused on print devices, but in 2008 they introduced the 24" DreamColor LP2480zx LCD display.
The DreamColor was developed, among other reasons, to serve as a replacement for CRT displays that were quickly becoming difficult to get ones hands on. So difficult, in fact, that several major Los Angeles facilities were hoarding Sony CRT displays in warehouses since there were so few alternatives. HP worked in close collaboration with DreamWorks Animation to design the product, and the LCD displays quickly became a go-to choice due to their accurate color reproduction and relative affordability.
In 2008, HP introduced a mobile version of the display for their HP EliteBook 8730w Mobile Workstation. This display was a TN (Twisted Nematic) Panel, which are relatively inexpensive and provide very fast response times (for this reason, they're very popular with gamers). Most TN panels are also quite limited in color, contrast and viewing angle....though the HP DreamColor was far superior to your run of the mill panels.
In 2010, HP released an improved display for notebooks, utilizing an IPS (In Plane Switching) panel for the 8540w and 8740w mobile workstations. This helped provide a wider viewing angle along with increased color depth processing and 30-bit display (10-bits per color channel). Because of the IPS tech, the new panels do have a slower response time but the benefits of the increased color reproduction outweigh this. Compared to other LCD monitors such as the Eizo CG241W, I found the lag to be fairly comparable.
This new panel also seemed to fix some reports I found online of uneven color and impurities across the original 8730w display surface (corners and splotches reddish, etc). There were enough reports of problems with the old displays -- and none I could find with the new ones -- that seem to indicate the replacements are greatly improved. This is borne out in our testing. We found color reproduction across the display to be quite consistent -- no visible splotches or color variations can be seen on the display.
So how good is the 8740w DreamColor at displaying colors? First a bit of explanation about some explanatory graphics one might see when comparing color devices. The image above and to the left (CIE 1976 Chromaticity Diagram) is a representation of what the human eye can perceive -- the entire range of colors that we as humans view. A given printer or monitor can actually only recreate a subset of the range of colors our eye is able to perceive, and this can be shown on the graphic as a triangle. The image above and to the right shows the colors that can be displayed by the HP 24" LP2480zx as well as the display in the 17" 8740w EliteBook. The area enclosed by the triangle can be referred to as the gamut of the device. The vertices of the triangle show the maximum values of R, G, and B that the monitor or system is capable of producing.
As we mentioned earlier, if provided a 30-bit signal by the graphics card, the display can accurately produce over one billion color possibilities. On the EliteBook, there's no need to worry about the graphics card as the Quadro 5000M supports 30-bit graphics as does the installed WIndows 7. However, it's important to note that Applications also need to support this higher bit depth. Adobe's After Effects, Photoshop, and Premiere Pro CS5 all support 30-bit mode as do Scratch, and Fusion.
If we add in reference triangles for the sRGB/rec709 color space as well as Adobe RGB color space (shown to the right), you can see that these fit inside the monitor gamut. This means that the monitor is capable of displaying all colors from each of those color spaces. This also holds true for SMPTE-C. The DreamColor even gets quite close to reproducing all colors in what's commonly referred to as the DCI-P3 color space. This "unofficial" color space basically conveys the minimum requirements for a reference projection system according to the Digital Cinema Initiative.
Another part of the display processing pipeline is accurately remapping the colors so they are correctly displayed in a given color space. The DreamColor Engine supports multiple color space emulation presets, including native/full gamut (no internal color management applied), sRGB, AdobeRGB, SMPTE-C, Rec709, DCI-P3 emulation, plus one user-defined color space. In addition, these panels support user-definable white point adjustment. The engine operates with 12-bit processing to provide increased accuracy in transforming the actual colors into the corrected colors for a given display profile (such as Rec709). In native/full mode, the 10-bit information is directly used by the panel since no color transform is needed.
The bottom line about processing ? The 10-bit display provides a high level of color performance and the internal 12-bit processing ensures that any color transforms that need to be done are even cleaner. This holds true even if you're feeding it 8-bit color information (from an application which doesn't support 10-bit color). The built-in display also supports multiple refresh rates of 47, 48, 50, 59, and 60 Hertz in order to reduce tearing at common video production formats.
One thing that's important to point out is that this display is *not* identical in performance to it's desktop big brother. As you've seen in the graphics above, it does not have the same color range as the desktop monitor, though this difference is relatively minor. It's maximum brightness is also less, weighing in at 210 cd/m2 vs. 250 cd/m2 -- though in general under controlled conditions you're not going to be running the brightness at it's maximum level. The contrast ratio is also less, at 800:1 compared to 1000:1 for the desktop manual (both displays forsake the scourge that is dynamic brightness).
That being said, these differences are minor when you consider much of this discussion is all about the balance of creating an ideal mobile workstation. It's about not bringing along a tower and instead finding a sweet spot of performance and portability. In this framework, there's no denying that having a slightly less "spec-tastic" DreamColor display is a great thing and one reason we think the EliteBook is a fantastic package. DreamColor in the field? Cool.
The next step of the puzzle is profiling the monitor to ensure that colors are displaying correctly. In our next article, we'll be taking a look at the tools to make this happen.
Don't forget about our EliteBook giveaway -- we're giving away an identical version of this computer to one of our readers. Check out our post about the giveaway for details on how you can get it in your hands.
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