Hitachi P42H401 Ultravision Plasma HDTV HT Labs Measures

HT Labs Measures: Hitachi P42H401 Ultravision Plasma HDTV



Full-On/Full-Off Contrast Ratio—259:1;
ANSI Contrast Ratio—414:1

Measured Resolution with the Leader LT-446:
480/720p/1080i: See text below

DC Restoration (poor, average, good, excellent): Excellent

Color Decoder (poor, average, good, excellent): Good

Measured Color Points:
Red Color Point: x=0.355, y=0.326
Green Color Point: x=0.241, y=0.692
Blue Color Point: x=0.152, y=0.066

The top chart shows the P42H401's gray scale relative to its color temperature at various levels of intensity, or brightness (20 IRE is dark gray; 100 IRE is bright white). The gray scale as set by the factory, in the Standard color-temperature mode and the Night picture mode, measures slightly warm with dark images and slightly cool with brighter images. After making adjustments using the Photo Research PR-650, the gray scale measures pretty close to the same, if not very slightly closer to D6500, the accurate color temperature, across the range.

The bottom chart shows the gray scale (or color temperature) relative to the color points of the display's red, green, and blue phosphors. These are somewhat off those specified by SMPTE. Red is slightly oversaturated. Blue is very slightly undersaturated and very slightly greenish-blue. Green is extremely oversaturated and somewhat bluish-green.

After calibration, and using a full-field 100-IRE white (21.74 foot-lamberts) and a full-field 0-IRE black (0.084 ft-L), the contrast ratio was 259:1. Using a 16-box checkerboard pattern (ANSI contrast), the contrast ratio was 414:1. On a 100-IRE window, the P42H401 produced 57.27 ft-L. (It is normal for a plasma to have lower light output on a full-white field versus a white window.)

Resolution is tricky, as this is the first display we've measured with (on paper, at least) more vertical resolution than horizontal. So, our normal (and admittedly rather archaic) way of reporting resolution would be somewhat misleading in this case. Using our Leader LT-446, 720p resolution is roughly 500 by 720, while 1080i is 580 by 940. These numbers are lower than what we've measured on other flat panels of similar resolution (as in, around the 1024 by 1080 of this TV). As the vertical resolution doesn't seem to be affected much, this probably doesn't have anything to do with ALiS/HD1080 and more to do with this specific model's internal processing.—GM

Hitachi Home Electronics