How to Calibrate Your HDTV
Initial Tweaks and Color Management
Before we dove into the intricacies of the color management system, however, we checked out the basic settings. Depending on your HDTV, you may not need fancy tools or software. The Picture Wizard in the LG HDTV, for example, offered an easy way to eyeball fundamental settings such as sharpness levels.
Heron also collected the results for the THX Bright Room setting I’d been using to break in the plasma set. We used this figure as a reference, since it’s a fixed setting. The color temperature actually was close to the desired D6500 (maybe a bit high, toward D6700). The color balance wasn’t perfect, though.
Each set of three bars represents various RGB settings at IRE ranging from 20 to 100. You want all those bars to be flat at the 100 mark on the Y-axis for each of the IRE settings. In the results shown here, green seems a little low, while blue and red are a bit high, on average.
The gamma was a little off--but then again, that was no surprise with a fixed setting tuned for brightly lit rooms.
Once we had collected the precalibration data, the next move was to change the menu settings from THX Bright Room to ISF mode 1, giving Heron access to all the settings, including the color management system.
The first calibration step was to tune the gamma. Dialing it to the 2.2 setting took only about 15 minutes; in fact, the ISF mode 1 “warm” setting was already pretty close. Heron also tweaked the grayscale tracking at this point.
Next, we started tuning individual levels for each primary and secondary color. This is where the process got repetitious. After we spent several hours tweaking each individual primary and second color, the final tuning looked like this.
It’s not perfect, but you never hit perfection--you just get as close as you can across the IRE range. One reason you can’t reach perfection is the interaction between settings: For instance, we’d tune the settings at IRE 90 and hit near-perfection, only to find out that the color balance at IRE 70 had shifted way out of whack. What we ended up with represented the best compromise we could reach.
If you look at the CIE chart at the lower left of the screenshot above, you’ll see that we nailed the colors fairly closely. All in all, it looks pretty good.
The Numbers Aren't the Only Concern
It’s possible to get a seemingly perfect set of numbers for most of the settings, and then discover that the actual image quality isn’t what you expect. Each person’s eye and brain differ in visual acuity and perception, and what may seem ideal in the lab might look harsh or off to your eye. In fact, when I first fired up my LG plasma, I thought it looked too “warm,” but I was coming from a rear-projection LCoS unit, which was in actuality too blue.
The visual quality differences I now perceive, after my set's calibration, are somewhat subtle. Dark areas of a scene certainly have better detail, and colors seem natural. If I shift between the THX Cinema and ISF 1 settings, I don’t see huge differences, though I tend to prefer the calibrated ISF 1 setting by a hair. On the other hand, the difference between THX Bright Room and ISF 1 is noticeable, and in that comparison I definitely prefer the calibrated setting.
Is calibration worth the cost and time? In my case, it’s still a little early to tell, but once again it depends on your viewing habits and your eye. Robert Heron will be dropping by my place for a follow-up session after doing some digging to tweak some of the settings further. Maybe we’ll get my HDTV even closer to perfect.
How to Calibrate Your HDTV