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

From: Stephen Williams (
Date: Fri Dec 08 2000 - 15:12:32 PST

  • Next message: Denny Lee: "HP Scanjet 5 qustion" said:
    > While it may be impractical to preserve the original document (these
    > are family records, not national treasures) it should be possible to
    > scan them and preserve their information. Once digitised, they can be
    > copied ad infinitum with no loss in quality.

    A couple issues that may well already know.

    First, there is not just the resolution to think about but the spectral
    response of the scanner. It is fiendishly difficult to get the right
    combination of illumination, color filters, optics and CCD to make most
    colors come out right. I wonder if consumer scanners can cope at the
    level you seem to be asking for.

    Second, it is not theoretically possible to "accurately reproduce
    color." Perfectly accurate "color" has a continuous spectrum that would
    require a near infinite number of channels to reproduce. All scanning,
    printing and color display depend on the human perceptual trick that aliases
    many colors together. It is a miraculous stroke of technical luck that most
    color perceptions can be aliased to colors produced from small sets of

    Imagine if hearing could be similarly tricked using only three pitches:-)

    Steve Williams                "The woods are lovely, dark and deep.              But I have promises to keep,            and lines to code before I sleep,       And lines to code before I sleep."

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