Martin Weberg wrote:
DTP94 and i1pro, in this case (still different manufacturers). Or is i1display and DTP94 internally the same?
I think they are of different origin.
But, shouldn't this be corrected for at factory calibration, one might think?
If there are optical differences between instruments, then this doesn't help. You could get two instruments to agree perfectly with one setup (one emission spectrum and angular distribution), and have them disagree with on some other display that has a different spectrum and angular distribution (or in the case of an LCD, a different polarization). I have no idea what the long term drift is either. Unlike the black level or reflective instrument calibration, there is no simple way to ensure emissive calibration, since a stable reference source is expensive.
I'm curious. What is a calibration factor? What is measured, in what units?
For this type of calibration it's simply a scale factor. The units are the Y value in cd/m^2.
DTP94 LCD 1032.03 DTP94 CRT 996.59
Is this the Argyll or GM driver readings?
It doesn't matter for the DTP94, since these are literally the numbers the instrument produces (ie. unlike the i1's, it has a fully "cooked" interface and spits out the XYZ as ASCII strings. If you run with the -D option, you can even see them). Graeme Gill.