Re: Zipping image files

From: Anthony Troncale (troncale@AMNH.ORG)
Date: Tue Jan 29 2002 - 11:12:44 CST

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    Message-Id: <200201291712.g0THCEg15698@sitelicense.arizona.edu>
Date:         Tue, 29 Jan 2002 12:12:44 -0500
From: Anthony Troncale <mailto:troncale@AMNH.ORG>
Subject:      Re: Zipping image files
To: mailto:IMAGELIB@LISTSERV.ARIZONA.EDU

    <pre> Question: Does Zipping or any other compression of a TIFF file change the color profile of a color image? Header information?

    Anthony Troncale American Museum of Natural History

    At 09:58 AM 1/29/02 -0700, you wrote:
    >As a couple of other people pointed out, both TIFF and the ZIP format use a
    >non-lossy compression format -- your gains will be minimal at best if you're
    >using a compressed TIFF. I can, however, see one argument of when using ZIP
    >on TIFF files might make sense:
    >
    >If all of your files are uncompressed TIFF (regardless of type; bitonal,
    >greyscale, colour, etc.), then for archiving purposes, you only need to
    >emulate two applications: one for decoding an uncompressed TIFF and one for
    >unzipping instead of having an application that has to handle multple
    >compression algorithms. This could simplify archiving -- I believe there's
    >an open-source version of ZIP (gzip) and the general TIFF format is a
    >published spec. so both could be implemented in new platforms in the future
    >relatively easily. Using proprietary algorithms (as could be bundled into
    >TIFF -- the spec. really doesn't care what compression algorithm you use)
    >might have implications from an archiving perspective.
    >
    >Tim
    >---------
    >Tim Au Yeung
    >Manager, Digitization Initiatives
    >Information Resources
    >University of Calgary
    >
    >
    >----- Original Message -----
    >From: "David Adams" <mailto:David.Adams@NATLIB.GOVT.NZ>
    >To: <mailto:IMAGELIB@LISTSERV.ARIZONA.EDU>
    >Sent: Monday, January 28, 2002 12:41 PM
    >Subject: Zipping image files
    >
    >
    > >
    > > Does anyone know if there is any form of change to digital image files by
    >using WinZIP or 'zipping' applications?
    > >
    > > I am interested to know if this will have an affect on TIFF files that are
    >to be used for long term preservation.

    </pre>

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