Panasonic TH-42PX500U Plasma HDTV HT Labs Measures
Full-On/Full-Off Contrast Ratio—779:1; ANSI Contrast Ratio—364:1
Measured Resolution with the Leader LT-446:
480: 480 (per picture height)
720p: 380 (pph)
1080i: 680 (pph)
DC Restoration (poor, average, good, excellent): Good (poor in Vivid and Standard modes)
Color Decoder (poor, average, good, excellent): Average
Measured Color Points:
Red Color Point: x=0.661, y=0.328
Green Color Point: x=0.257, y=0.666Blue
Color Point: x=0.148, y=0.063
The left chart shows the TH-42PX500U'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 warm color-temperature mode and the cinema picture mode, measures slightly warm with dark images and warmer still with brighter images. After making adjustments using the Photo Research PR-650, the gray scale measures better, within 197 Kelvin of D6500, the accurate color temperature, across the entire range.
The right 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 from those specified by SMPTE. Red is somewhat oversaturated, while blue is slightly oversaturated and slightly purplish-blue. Green is oversaturated and slightly bluish-green.
After calibration, and using a full-field 100-IRE white (21.03 foot-lamberts) and a full-field 0-IRE black (.027 ft-L), the contrast ratio was 779:1. Using a 16-box checkerboard pattern (ANSI contrast), the contrast ratio was 364:1. Despite having a black-level control, this only adjusts gamma, not actual black level. On a 100-IRE window, the plasma produced 55.01 ft-L. (It is normal for a plasma to have lower light output on a full-field white versus a white window.)—GM