Calibration Notes for Video Reviews

The Perfect Vision #74, January 2007

JVC LT-46FN97 | Mitsubishi WD-57831 | Optoma HD81 | Toshiba 42LX196

JVC LT-46FN97

Pre-calibration, the grayscale was leaning toward blue. A dynamic picture circuit was enabled that changed video levels based on the average picture level of the image. There was also significant edge enhancement and inaccurate color decoding. The backlight (called "energy saver mode") was turned up all the way. The display does not pass below black information on the HDMI input. The display's Full Native mode provides 1:1 pixel mapping at 1080i/p, but two lines are still missing on the right side. Turning off the various enhancement controls minimized the dynamic video levels, but the levels still changed based on average picture level. The display failed the HQV noise-reduction tests, but it did a better job with the rest of this material than the majority of displays we've tested.

Mitsubishi WD-57831

Out of the box, the display had a significant amount of edge enhancement, a grayscale that tended toward blue (upwards of 11,500K), and inaccurate gamma, color decoder, and primary/secondary colors. In general, video levels were set incorrectly. There is a dynamic circuit that changes video levels based image information, but it is slow to respond. Post-calibration, the display's grayscale tracked respectably, but hardly as well as the other displays we have evaluated in its' class. The on/off contrast ratio was impressive, but the ANSI contrast ratio was low at 186:1, which could be due, in part, to the high gain of the screen. Color primaries and secondaries could not be adjusted to meet the specification, but it appears that Mitsubishi is thinking about adding this capability to the display: there are factory menu adjustments that seem intended to adjust the primaries and secondaries, but they were inactive in the sample we tested. Hopefully, Mitsubishi will activate this system so that accurate colorimetry may be achieved.

Optoma HD81

Out of the box, the projector's color decoding was incorrect with desaturated color, but edge enhancement was non-existent, something rarely seen these days. The projector also provided 1:1 pixel mapping from the start, allowing 1080i/p sources to look their best without unnecessary processing. Black level and contrast were set quite well from the start. The grayscale was closer to correct than the majority of displays; we were using a Stewart Grayhawk RS screen which is known for its excellent spectral response. If we had used a different screen, the grayscale might not have been as accurate. The user controls and remote work very slowly, a huge disadvantage when working on a display. Looking at the component input at 1080i, there is some noise in the high-frequency section of the chrominance channels. The projector did quite well with the HQV video processing tests.

Toshiba 42LX196

Out of the box, the brightness and contrast were high causing black to appear gray and white to clip. The grayscale tended toward blue (upwards of 15,000K) with an inaccurate gamma curve. The color decoding was off with desaturated colors, and there was a significant amount of edge enhancement. The Native aspect-ratio mode provides 1:1 pixel mapping at 1080i/p. After calibration, the display had excellent frequency response, a very flat grayscale, and an accurate color decoder. However, its primary and secondary color points were unable to be adjusted to meet the specification. A significant amount of light output was lost in the calibrated image, which is due to bringing the backlight setting down to achieve an acceptable black level. The display did very well on the HQV tests, only failing two, which is quite a bit better than the majority of displays we've tested.

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