Densitometers have these polarising filters but specros like i1Pro don't have polarising filters !. Some software can simulate a filter but nothing comes close to real filters.PERIOD!? Have you never heard of a spectrophotometer? They are able to produce density measurements with zero need for a densitometer. Please explain why one would use a densitometer when a spectro can provide the same measurements and SO much more as well.
Older spectros like spectrolino do have all kinds of filters (UV, polarisong etc.) but by 2012 they will no longer be accepted for re-certification by x-rite. That's right X-rite is badd ass company if you ask me :(