Re: Which scanners REALLY provide 36 bit output? HP?

From: Steffen Kluge (
Date: Sun Dec 10 2000 - 17:43:01 PST

  • Next message: Warren Young: "Re: Which scanners REALLY provide 36 bit output? HP?"

    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.


    Steffen Kluge <>
    Fujitsu Australia Ltd
    Keywords: photography, Mozart, UNIX, Islay Malt, dark skies

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