On Sat, Dec 09, 2000 at 11:00:06AM +0800, Steve Underwood wrote:
> > represent all the information possible. For 19th century photography I
> > believe 1200 dpi comes very close to this.
>
> This is about the resolution of most modern emulsions (unless you are using
> super slow specialist films). I doubt the 19th centruy emulsions have
> anything like that resolution. 19th century lenses are incapable of
> resolving this well, anyway. Such a high resolution would only make sense
> when scanning documents, or maybe paintings.
>
> The resolution of most film images are much poorer than most people
> realise.
Well, all decent 100ASA slide or negative emulsions are capable
of recording in excess of 100 lines/mm, at a contrast of
1:1000. That would be 2500lpi. Good lenses can get across maybe
about 1200~2000lpi. Keep in mind that the pixels in a film
emulsion are scattered (and different in size), so you need a
lot more pixels in an orderly rectangular grid to get the same
visual resolution.
Cheers
Steffen.
-- Steffen Kluge <kluge@fujitsu.com.au> Fujitsu Australia Ltd Keywords: photography, Mozart, UNIX, Islay Malt, dark skies ---- Source code, list archive, and docs: http://www.mostang.com/sane/ To unsubscribe: echo unsubscribe sane-devel | mail majordomo@mostang.com
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