I can't say I really understand what the HCFR folks are doing with their reference
files. It doesn't make any sense to me that they can "calibrate" an instrument
without an independent reference of some sort. So what I've done with
my driver is to hard code a reference of the particular HCFR I have
into the software. The reference was created by calibrating against
an X-Rite DTP94 on two particular displays. The validity of this calibration
depends greatly on the uniformity of manufacture of the optical sensor,
and the similarity of the spectral characteristics of the displays to
what is actually being measured. Without some sort of manufacturers
factory calibration for each HCFR instrument, I don't see what
else can be done for it.