I'm with David Brown on this. Once I'm dead who cares about my prints unless I'm a news photographer, which I'm not. As for negatives, even in the case of famous photographers there's no real value to new prints made from negatives after the photographer is dead. So I'd say people who worry about their negatives lasting hundreds of years are all ego. Nobody's negatives need to outlast the photographer.
C'mon - this is nonsense.
Stop worrying about grain, resolution, sharpness, and everything else that doesn't have a damn thing to do with substance.