The major film studios, faced with a related problem a long time ago, opted for a method called YCM separation, where they separate the image into yellow, cyan and magenta and record it onto very stable black and white polyester film stock. Properly stored, this supposedly has a lifetime of 500 years or more.
A modern laser film recorder is capable of a resolution of 4096x3112 and 10 bits per pixel, so that's about 16MB of data per 35mm frame with black and white film.
A modern laser film recorder is capable of a resolution of 4096x3112 and 10 bits per pixel, so that's about 16MB of data per 35mm frame with black and white film.