Last year I scanned all the parent photo archive of slides and negatives. Before to share the experience, to quote the answer of Sergei Alexandrovich
Scan with the maximum resolution - there really is NO need.
Scan with the maximum resolution is really NOT
necessary. The reason of scratches and other imperfections that occur in almost every frame. When you're scanning at a low resolution, and then removed the defects, the picture quality suffers greatly.
I scanned on a Plustek OpticFilm 8100
The scanner can scan negatives and positives in the flesh resolution up to 7200 ppi.
The scanner is attached to a special frame holders for film. Every film (which is usually 36 frames) cut into pieces on 6 frames and inserted into the frame. After scanning, the film will be slivered.Scanning in color and b/W negatives
Don't know what there is obtained after scanning at 1200 ppi ( from the words of Sergei Alexandrovich), but the result seems to want users to "kontaktika", but no more.
The scanner is able to do a quick pre-scan, after which it becomes clear whether or not to spend time scanning the frame in high resolution. My eye is not a diamond, but the difference in detail between scans at 2400ppi and 3600ppi notice. To scan at 7200ppi makes sense when there is a rare frame where a lot of scratches. The scanner comes with special software SilverFast Ai Studio, which you can use to remove scratches in smart mode. In practice it turned out that with scratches all cope better Photoshop.The algorithm for processing color negatives:
1) Pre-scan, visually determined by the value of the frame.
2) If the frame is serial, then scan at 3600ppi. If the frame is rare and valuable, then scan at 7200ppi. No optimizations means SilverFast Ai Studio is not running, just saved raw to TIFF.
3) In Photoshop do color correction, change the contrast and remove scratches. If scanning at 7200ppi, after processing to reduce the resolution of 3600ppi and save.
On B/W negatives detailing above, than on color and stronger noticeable scratches.
As for slides (positive), then it is possible to scan at 2400ppi.
A little about the size and permissions:
7200ppi in TIFF format in color => scanning a single frame of 3:56 min => resolution 10260х6844 => file size is ~200 MB.
7200ppi in TIFF format B/W => resolution 10260х6844 => scanning a single frame of 3:56 min => file size: ~68 MB.
3600ppi in TIFF format in color => scanning time of one shot 1:25 min => resolution 5130х3422 => file size: ~52 MB.
3600ppi in TIFF format B/W => scanning time of one shot 1:25 min => resolution 5130х3422 => file size of ~18 MB.