Grain in the sky is by product of scanning Provia 100F, which is a well known issue as 'Pepper Grain'. On the light table it doesn't show up but in scan it shows and can be quite bad, it is (was?)on certain batches of 100F and allegedly caused by tiny air bubbles in the film sheet, and I was a lucky one to pick one :-).
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{K:22030} 2/6/2004