I have a Nikon Cool Scan VED scanner. I just started to scan
30 years of slides. I got thru the 1st 30 with ease, then the next
one was bleached out quite a bit. I did the preview scan, and it
looked ok. What I got with the real scan was a negative rather
than a positive. I need a clue as to what I might have done
that I should not have done.

Thanks

Art L

The Nikon scan software has a setting for film type. Make sure it set to the type of film you use. First thing I'd check anyway.