Considering a 1000-ft. roll of standard black-and-white film we talk about some $400 generating cost. Since that roll will last about 400 years the archiving cost per anno is $1 for it. A 1000-ft. roll of 35-mm. film contains 16,000 frames of 24 mm × 18 mm. Given a resolution of 200 line pairs per millimeter we have 17.28 Megapixel available, the roll thus holding 276.48 Gigapixel. Encoded 34.56 Gigabytes
Raising the resolving power of the overall system we could go to Terabytes. If not used numerically, the photoreprographic quality of modern films allows archiving in fantastic fineness. Actually, there are stocks on the market that have resolving power up to 5000 line pairs per millimeter, grainless.
He who believes in digital archives is ignorant.