How to Calibrate Your HDTV
We all know that we're supposed to get our HDTV sets calibrated by an expert if we want them to look their very best. (We also know that we're supposed to floss daily.) But in this era of THX-approved presets and LED-backlit 3D TVs, how much difference does a professional calibration make? I decided to find out for myself with my new LG 60PZ750 plasma TV.
The 60PZ750 is a 60-inch plasma HDTV with THX and ISF (Imaging Science Foundation) certifications, network connectivity, and support for stereoscopic 3D video. It has THX settings for cinema and bright-room modes; I could have just used those settings and been mostly happy. Being a curious geek, however, I wanted to explore the process of calibrating the display.
The set's THX modes are pretty locked in--you can make just a few minor changes. THX works with the TV makers, offering THX certification in an effort to replicate the experience of the video editor’s control booth. Although THX modes mostly work well, rooms differ, lighting is imperfect, and every HDTV's characteristics can change over time.
The ISF modes are quite different, exposing a huge array of individual settings suitable for professional calibration. You can fool around with two-point grayscale calibration, or change the settings for 20 different increments along the IRE scale (with 0 IRE being black and 100 IRE being all white).
As a digital-photography aficionado, I’ve calibrated my own desktop displays, and I could have gone the DIY route with my TV. In fact, I did fool around a bit with the Picture Wizard calibration tool built into the LG set. The Picture Wizard in LG’s higher-end HDTVs does an admirable job of walking you through basic calibration for black and color levels, and it’s a good first-level approximation.
But I decided to bring in a professional to see just how well this particular plasma HDTV could be calibrated. How much does professional calibration cost? How long does the procedure take? What tools are involved? Is calibration worth the investment?
Well, it depends. Are you a serious videophile who wants to watch film and video as the directors envisioned? Or are you a casual viewer of mostly sports, in a bright room? Your viewing habits and interests will help determine whether you’re a good candidate for professional calibration.
Consulting a Pro
Ideally, you don’t want to calibrate a brand-new HDTV out of the box--you want the unit to “settle in.” Depending on the display, the amount of time can range from 50 to 200 hours of use. I set up my LG 60PZ750 in the family room, and we watched shows for several weeks prior to scheduling calibration.
I selected Robert Heron to calibrate the HDTV. You may know Heron from HD Nation, Tekzilla, and other Web-video tech shows; he has also written tech articles for a number of publications. He builds his own gaming rigs, and is a general all-around tech nerd.
Heron is also a hard-core videophile who has gone through all the training and certifications for calibrating HDTVs, including both THX and ISF training classes. On occasion he consults for HDTV panel manufacturers and resellers. I’ve watched both his knowledge and his passion for video grow exponentially since he first started reviewing HDTVs. For calibrating a single LCD or plasma HDTV, he charges $350.
Interestingly, I didn’t have to prepare the room at all. My family room can be fairly bright throughout the day, because one wall has an 8-foot glass patio door. Although blinds cover the glass door, they aren't enough to block the light entirely. Light leakage wouldn’t be an issue during the calibration, however, since the sensor Heron normally uses stays close to the HDTV.
Heron arrived with a rolling cart full of gear, but for the most part he used this sensor.
The X-Rite i1Pro is a spectrophotometer that’s a little slow but mounts against the display, minimizing the effect of stray light.
Heron uses SpectraCal’s CalMAN version 4 for collecting and analyzing data from the i1Pro.
One of the problems that have traditionally plagued HDTV calibration is the difficulty of accessing all the color-management tools built into the TV itself. In older HDTVs, these settings were often called the “factory” or “service” menus, and were accessible only if you pressed a special key sequence on the remote.
However, the 60PZ750 has full ISF support, which exposes the HDTV's color management system. The CMS contains highly granular controls, with individual adjustments for both primary and secondary colors, as well as for tint and contrast.
Calibration consists of taking measurements with the sensor, capturing them on a PC running CalMAN, and determining how closely the measured settings adhere to the ideal. For example, the ideal grayscale color temperature is D6500 (6500 kelvins) across all grayscale levels, from 10 percent to 100 percent, for each color.
Next page: Initial tweaks and color management
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