In scanning about 8000 slides and prints, I found that the color correction software that came with my Epson V500 scanner was very effective on most faded images. A few of the slides were unrecoverable. Those I scanned in black and white.
The most important images I scanned in both JPEG and in TIFF, just so I would not have to come back to the job. All the JPEG images have been fine for my purposes, and the file sizes much more manageable..