[KPhotoAlbum] Importing and Exporting tags

Robert L Krawitz rlk at alum.mit.edu
Sun Jun 18 22:23:29 CEST 2006

   Date: Sun, 18 Jun 2006 19:56:32 +0200
   From: Marco Molteni <marco.molteni at laposte.net>

   Ashley J Gittins wrote:
   > On Sunday 18 June 2006 20:35, Rui Malheiro wrote:
   >> I think it would be great to have a standard XML format so that every image
   >> browser/manager could pickup tags when displaying an image.
   > Sounds like a job for IPCT tags (since I think that's what they
   > were invented for) - does anyone know if there is a standardised
   > method/format for placing them in separate files (like a
   > image.jpg.ipct) rather than embedding the info into the image
   > file itself? I am thinking of cases where the original format
   > (raw files) may not support iptc or where people don't want their
   > originals modified at any cost.

   It *is* a job for IPTC.

   And I really cannot understand why so many people don't want their
   image files modified.

I'll give you a few reasons why:

1) Paranoia (don't do anything to your negative!)

1a) The image may be stored on read-only media.

2) Some cameras are able to "sign" images, to prove that they haven't
been manipulated after the shot was taken and to prove which camera
took the shot.  Some of the higher end Canon cameras can do this;
there's special software Canon makes available to verify the
signature.  Admittedly I don't know whether adding IPCT tags breaks
the signature or not, but police or others who need this kind of
signature may well have policies that image files must not be modified
in any way whatsoever (chain of custody and all that) but who still
need to tag images to reflect which investigation they're related to.

   Let's look at how professionals manage their workflow: they tag
   their images with IPTC keywords, that are stored INSIDE their raw

   Why? Interoperability. As simple as that.

   All the XML or binary databases or whatever can just be used as a
   quick lookup cache, or maybe for file formats that do not support
   IPTC tagging.

   And please spare me the "I am afraid that storing the IPTC keywords
   in the file might corrupt it". This is pure nonsense. There are
   well-known algorithms to preserve a file and commit (in database
   jargon) a new version only when it is safe to do so.

Sorry, I'm not going to spare you this "nonsense".  I know that it's
possible to do this, but it adds complexity and it's possible that the
code has a bug in it.  Certainly it's possible that cp also has a bug,
but a) it's much less likely and b) the fewer things modifying images
the better.

Robert Krawitz                                     <rlk at alum.mit.edu>

Tall Clubs International  --  http://www.tall.org/ or 1-888-IM-TALL-2
Member of the League for Programming Freedom -- mail lpf at uunet.uu.net
Project lead for Gutenprint   --    http://gimp-print.sourceforge.net

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