I recently purchased used Polaroid SprintScan 45 Ultra on eBay. I'm extremely happy with the quality of scans, fine detail rendition etc. However, my colors seem to be way off - like some magenta cast, and sky colors look weird too. I'm wondering if anyone has any suggestions on how to improve the color reproduction. I shoot 4x5 on Velvia 100 and scan them using SilverFast AI. I also tried to install Vuescan but it can't find the scanner (although the doc says that SprintScan 45 Ultra is supported).
If anyone has any experience with this scanner and can share some tips, I'll appreciate it.

Thanks a lot!

Eugene.