Film Grain and Negative Scanning: Grain Aliasing

When scanning negatives, it is sometimes apparent that there is a lot of grain in the film. Pictures of the sky that printed nice and smoothly from a negative start to appear bery speckled in the scan.

There are two main reasons for this: First: you may be 'pixel peeping'. That is, you use the handy magnifier glass and enlarge the picturer to something that is more like a giant A3 englargement. You never looked at a film print as an A4 enlargement and then stood 50-80 cm from it. If you had, it owuld have looked a lot less clear.

The other possible cause of scanned films appearing specked is something called Digital Aliasing. This happens when the resolution of the film scanner is somewhere in the vicinity of the size of the original film grain. The two interfere with each other in a way that then exaggerates the grain.

Have a look here for an article by P.L. Andrews that describes the idea of digital grain.

(DIgital GEM?) may offer a way to reduce grain.

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