[KimDaBa] new feature: IPTC keywords

Marco Molteni molter at tin.it
Sun Oct 23 20:08:59 BST 2005


On Sun, 23 Oct 2005 12:39:55 -0400
Robert L Krawitz <rlk at alum.mit.edu> wrote:

>    Date: Sun, 23 Oct 2005 18:23:47 +0200
>    From: Dotan Cohen <dotancohen at gmail.com>
> 
>    On 10/18/05, Marco Molteni <molter at tin.it> wrote:
> 
>    > 2) keywords should stay in the image files themselves (and
>    > eventually cached in a database or the equivalent index.xml
>    > file), because IPTC is a standard and you get automatic
>    > interoperability by storing the keywords in the files.
> 
>    I see that I got to this thread a little late. I second the opinion
>    that there is a definite need for IPTC support in a product such as
>    KimDaBa.

[..]

> Do the keywords actually need to be kept in the master image files at
> all times, or can they be added separately (during export, for
> example)?

>From an IPTC point of view, the keywords must stay in the image since
the beginning, without the need of an export phase. Otherwise the
potographer would have to remember that he cannot upload photos directly
but that he has to export them before.

> I can see good points both ways.  I think it's an excellent design
> point to have Kimdaba never modify the master files (it's possible to
> be comfortable that no matter what you do you won't mess up the images
> -- plugins excepted), but it also makes sense to be able to store
> keywords in images, particularly if there's a standard for it.
> 
> If you added keywords in only during export, you could preserve both
> properties, although obviously at the cost of extra disk space.
> Adding them into the master files has to be programmed very carefully;
> it's very easy to lose data if you're not extremely careful.  There
> are lots of corner cases (computer crashes at exactly the wrong
> moment, for example), and even something as mundane as different
> filesystems may be different in this regard.

I understand that kimdaba guarantees not to touch the images, and
that many users like it that way. The easiest way to keep the current
behavior might be the following:
- default as today, no IPTC keywords, images untouched.
- if IPTC keywords is enabled, then the keywords are stored in
  the images.

I agree that updating an image file must be done carefully, but it
is a well-known field (it is a transaction). For example MUAs
(mail user agents) do this every day and you normally don't loose
your mail ;-)

> BTW, I'm not convinced that a plugin is the right way to do this;
> adding a keyword would change the MD5 hash, which is something the
> core application needs to know about.  I'm also dubious about an
> architecture that specifies that it won't change the file, but it's
> perfectly OK for a plugin to; users shouldn't really have to know
> about the difference between a plugin and the core application.

agreed on both points. On the other hand, if the plugin exported
the files with IPTC, then there would be no md5 problem (but this
is the solution I don't like)

marco





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