Sharp XV-Z30000 3D DLP Video Projector Grayscale and Color Gamut Update, 7/24/2012
Sharp XV-Z30000 Grayscale and Color Gamut Update
I was seriously impressed by Sharp’s newest home theater projector when we initially reviewed it for Home Theater, but I had reservations about its measured color performance. Fortunately, its subjective color, as judged in that review, would likely more than satisfy most viewers. But we’re a bit fussy about measured performance here at Home Theater, so I could not quite give this projector Top Pick status.
The problem at that time were in the Sharp’s lack of both a complete set of white balance controls and a useful color management system (CMS) that would allow adjustment of the primary and secondary color points that define the overall color gamut. For white balance, there was only a single set of overall red, green, and blue adjustments, rather than separate adjustments for the top and bottom of the brightness range. Fortunately, the single set of controls was able to dial in a more-than-respectable grayscale. But as a projection lamp ages, its spectral balance can shift enough that a single set of adjustments may no longer be sufficient for a good calibration—even though the lamp might still have hundreds of hours of useful life.
On the CMS side, as first reviewed, the projector offered adjustments for only two user-selected colors, and the ergonomics of the controls suggested that they were designed more for consumer fiddling than for serious calibration.
But as we went to press, Sharp informed us that it has incorporated both high and low white-balance adjustments and a full color management system into the XV-Z30000. The catch, at present, is that the added controls can be accessed only from a computer connected to the projector. While this addition is a firmware update that can be installed into early production models, Sharp offered to send us a second, updated sample, to which we quickly agreed.
My first attempts to access the new controls with a relatively new laptop were complicated by the fact that the control connection on the projector is RS-232 while the ports on my PC are USB only. Not wanting to fuss with a USB-to-serial converter (I’ve had issues with these in the past), I was able to rustle up a laptop with an RS-232 output. But making this work also required downloading a special program to enable the connection.
When I had no luck with this, Sharp actually loaned me a compatible laptop computer. With this, and more than a little telephone assistance, I was finally able to access the new controls. Calibrators and others more adept with PCs than I am may well have an easier time with this process. (I’m mainly a Mac person, and even there I’m far from a power user.)
I gave up quickly on the additional white-balance controls; they appeared to do little. And truth be told, there wasn’t much that needed doing; with about 175 hours on the lamp, the grayscale delta E averaged 1.11 and was never higher than 2.05. It was the color gamut that needed the most help, and that’s where the new CMS comes in.
The range and ease of use of this computer-controlled arrangement does leave a lot to be desired compared to the CMSs I’ve used on many other displays, including Sharp’s own flat panels. But the new CMS adjustments did produce definite changes. I was able to pull most of the color points and luminance values closer to the requirements of the Rec. 709 color gamut (see the CIE chart above), with the final overall color delta E averaging a very good 2.65. As you can see from the accompanying chart, green was the outlier with a delta E of 4.99. Cyan also could have used more tweaking than the CMS offered, with its delta E of 5.16. But cyan is a combination of blue and green, and with green off so much, the cyan limitation was no surprise.
One could argue that the oversaturated greens in the initial review are preferable to the green position achieved with the new controls. Is the new setting an improvement or merely a change? That might be a difficult call. But certainly some of the other colors, as well as the color luminance values (the third dimension not visible in a 2D CIE chart) were much improved. I suspect the reason that green deviates as much as it does in either situation, and cannot be fully corrected, is a limitation in the green filter in the DLP color wheel, which may have been chosen to favor brightness over color accuracy. But a 10-15 percent loss of brightness would hardly be noticed here—at least in 2D. The above measurements were made on a 101-inch wide Elite screen (gain 1.1), in the High Brightness setting, and produced a peak white output of nearly 21 foot-lamberts.
I also did some additional work on the custom gamma mode, which resulted in an overall gamma of 2.27 (low 2.07 at 90%, high 2.42 at 40%). While the result looked good, further adjustments might make it even better. But more steps in the Custom Gamma menu would be a plus, particularly at 90% where there is no control.
I continue to be impressed by everything else about the Sharp XV-Z30000, from its good (though not trend-setting) blacks to its superlative picture detail. Now, with the addition of the new calibration controls, the circle is nearly complete. Yes, these controls should ideally be in the user menus—or at least in a service menu where they can be accessed without a computer. And the computer arrangement does not provide for separate 2D and 3D calibration of both color gamut and white balance. In other words, we’d like to see the same the same kind of white balance and color gamut control here that Sharp currently offers in its high-end LCD flat panels. Nevertheless, the availability of these controls, even if it requires a computer, now elevates the XV-Z30000 to Top Picks status. Thomas J. Norton