Am 25.09.2012 04:57, schrieb Michael Nagel: > Florian, > > thank you for your detailed response. > > regarding (1): > > I did look at the user logs and found the report when it created when > dispcal created the correction matrix - but there is no information in there > though on the drift of the colorimeter compared to the spectro. > > Is this info only coming up when you just created a correction matrix and is > not stored in the user log files ? I'm not sure I understand you correctly. Is it really instrument drift you are interested in or rather the match (or error) between spectro and colorimeter (I'm assuming the former, because the latter seems out of scope for an utility like ccxxmake)? The matrix itself is the correction needed for the colorimeter readings to largely match the spectro readings, so the matrix already tells you something (e.g. if both instruments gave exactly the same readings, you'd have the identity matrix), but it's probably hard to interpret. Maybe you're looking for some other metrics like delta E between the set of test patches measured by the spectro and the colorimeter? Argyll's 'verify' tool can do this. -- Florian Höch