The Perfect Vision

Calibration Notes for Hitachi 42HDX61/55HDX61

The 42HDX61, along with other Hitachi digital sets this year, has a user adjustable color decoder. Here’s the best way to set it using the Avia disk:

Find the following section in Avia: Advanced Avia / Video Calibrations / Video Test Patterns.

Calibrate your set’s brightness and contrast with the appropriate patterns on the test disk and turn down the room lights. Set the color temperature to STANDARD. Go into the color decoder section of the user menu while displaying the blue color bars found in Video Test Patterns / Color Adjustment / Standard Color Bars section of the disk.

You’ll first be using the blue bars to set the “color” and “tint” adjustments in the color decoder menu, but first you’ll need to create a blue screen by selecting “blue” in the menu. With only the blue color working, it’s easy to set these controls very precisely. Simply adjust “color” so that the saturation bars on the far left and right are a constant shade from top to bottom, then adjust “tint” so that the hue bars on the inside are are a constant shade as well. Recheck “color” after adjusting “tint.” These are the technically accurate settings of your color and tint controls (same ones that are in the video menu) with the particular source you’re using. It may not apply to other sources but the relationship of blue to red and green that you’ll set next should still be accurate with other sources.

Once overall color and tint are set with a blue screen, change the test pattern to red color bars, change the screen to red, and adjust the red level just as you did the blue. There is only a saturation adjustment so only look at the saturation bars on the test pattern. Don’t change the “tint” control. Repeat the same sequence for green.

Now red and green levels are correct relative to blue (which you set first) and your color decoder is accurate. Remember, this is totally separate from color temperature and grayscale. Grayscale deals with perfecting the black-and-white picture while color decoder adjustment deals with the balance of red, green, and blue which are added to black-and-white to make the final color picture.

Your calibrated values shouldn’t be very far from factory defaults or you probably did something wrong. This adjustment can be done separately for each color temperature preset but be aware that cooler color temperatures (especially “Cool”) will require additional red (more than the “measured” correct amount) from the color decoder to make flesh tones look right. This is where “red push” all started--to compensate for excess blue in factory set cool color temperatures.

“Color Management” isn’t quite so easily adjusted to perfection. In fact, there is no “perfect” setting of these controls since the color primaries aren’t perfect to begin with. Some have reduced red to compensate for “red push,” but that won’t be necessary after the color decoder has been corrected. An ISF technician can use a color analyzer to tweak the individual colors to industry specs (make sure he has the primary and secondary co-ordinates loaded in his laptop), but most of these can only be optimized but never totally perfected. I liked the result I got with most colors but had to pretty much leave green alone since it was (like with most digital displays) so far out of spec and difficult to accurately correct.

My review sample could have been defective but it had a significant grayscale shift toward green at dark gray (20 IRE) but only through the HDMI inputs. Since color temp calibration is global on this set (no separate calibration controls for various scan rates) the only workaround is to calibrate the “Neutral” preset for most inputs and another color temp preset (like “Black & White” or “Medium”) for HDMI inputs at 1080i. Getting the dark end of the grayscale right is essential for a truly impressive picture and your friendly ISF technician will easily be able to tell if your sample needs this extra step to perfect HDMI.