Message-Id: <200201291658.g0TGwVg12606@sitelicense.arizona.edu> Date: Tue, 29 Jan 2002 09:58:04 -0700 From: Tim Au Yeung <mailto:ytau@UCALGARY.CA> Subject: Re: Zipping image files To: mailto:IMAGELIB@LISTSERV.ARIZONA.EDU
<pre>
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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