Quote Originally Posted by kaif View Post
Just a slightly different thought re maximum scan resolution: Of course, for a specific project which will get printed relatively soon, it makes sense to work out how large you are going to print - and then work out a sensible scanning resolution based on that. If you later want to work on bigger prints or crops, you could re-scan as necessary.

But then, at least at C-41, Fuji for example gives an average live of 10 to 20 years for their negatives without any loss of quality, if I remember this rightly. So I imagine there is at least some argument for scanning at least colour negatives at the highest resolution you can achieve when you first archive them. (Which is really how I came to ask this question in the first place...) Of course that's somewhat different for b/w, where you'd hope your negatives have a much better live span.

Important color images can be preserved with color separation technique, this is making 3 contact copies on BW copy film, each copy made with a different basic light color, I guess that depending on if it is a positive or negative image CMY or RGB can be used.

In fact Hollywood color movies are even today stored in this way, including movies shot digitally. Kodak 2237 and 2238 films are used for this: "This black & white recorder film is intended for making archival separations from color digital masters", Kodak says.

For color sheets that technique is also possible with regular fine grained film. Another way is refrigeration (40°F (4.4°C) and 27% RH, for example), that slows chemical changes, and I guess that concurrent inert gas storage may be also good.