back to my question from a couple of weeks ago about i1 D2/LT "drift", just to add some data, here is a comparison of a grayscale measurement two years ago vs today, both measuring the performance of the default "cinema" picture mode in WARM color temp on my Panny 50PH10UK display.
This is the most consistent data point I had since one of the first things I checked when I got the 10UK and the probe two years ago was to check the grayscale at default values.
The top end seems pretty consistent but red is reading lower and blue higher at lower IRE's. Green still seems dead on... and the overall reading of the default warm grayscale being too green (a commonly noted issue with Panny PDP's) is still backed up by my eyes when I switch between my calibrated grayscale and the default warm. Gray window patterns are obviously greenish in default warm, as are skin tones, skies, etc. with real world content.
There are some other variables -- MLL has increased from 0.035ftL to 0.054ftL in the two years, and for some reason the 100% white is a little lower now.
Obviously it is impossible, without a reference, to attribute any of the drift to the probe vs the display. But it's pretty darn close two years later, seems close enough for my amateur uses
batpig 50P10UKA Marc 2008 vs Feb 2010.zip 1.62890625k . file