I own two i1Pro’s and I have a i1Pro2. When using the CalMAN software the i1Pro does require a black reading every ten minutes. I would say the i1Pro2 is a big improvement and worth getting. If you are still considering a i1Pro2 “buy it”. If the i1Pro drifts after thirty minutes that would mean during a calibration that the readings constantly becoming progressively worst before the calibration would be finished. Do you really think that this type of information would not have come out in full force on the internet? If you budget can handle it look at the Jedi. The only draw back to the Jedi is that it is not advisable to do continuous reads as the Jedi will require servicing after a time period but it is a very nice spectro.
