The primary color blue was dead on SMPTE standards. The small error in red thankfully went less toward orange. Green was considerably oversaturated but with less of a yellowish look than usual with LCD. The color decoder was accurate with no red or green emphasis whatsoever.
Color temperature (the critical "color" of a black-and-white picture before color is added) in NORMAL, the most useable mode, was slightly more bluish than the D6500 gray standard, measuring 8000K on bright patterns (80 IRE) dropping to 6900K on medium gray patterns (50 IRE). Below and above that, the grayscale became considerably bluish, especially below 50 IRE, where it was well over 10,000K as "black" was approached. This nonlinearity and excess blue were probably the entire reason for the loss of color in darker scenes. WARM measured 6000K at 80 IRE, dropping to 5400K at 50 IRE (both unacceptably reddish), but also went very bluish below that. This non-linear grayscale definitely holds the PT-52LCX65 back. Unfortunately, it's not correctable with an ISF calibration. Insufficient controls are given in the factory service menu. Light output was 90fL (above average) with a 100 IRE window pattern and nearly that with a full white screen. Black level measured a high 0.18fL giving a peak contrast ratio of 500. Subjectively, though, contrast was good only on bright scenes due to the high black level. ANSI contrast using a checkerboard pattern was low at only 130.
Black-level retention, the ability to hold a constant black level from dark to bright scenes, was very good. Geometry and centering were very good.