[Digikam-users] IPTC and tags, again... Questions to the team

Gilles Caulier caulier.gilles at kdemail.net
Wed Jan 10 12:26:38 GMT 2007

On Wednesday 10 January 2007 13:01, Daniel Bauer wrote:
> Hello digiKam team
> During the discussions about tags and how to save them to IPTC keywords
> once again I was thinking about the purpose and use of tags and IPTC
> keywords. I have some questions to the digiKam team, but first let me
> explain my point of view:
> I think there are at least 2 different needs depending on what tags and
> metadata should be used for. (I've pointed to this in the "saving tags and
> rating into IPTC tags..."-thread march last year):
> a) "home use" and needs of digiKam itself:
> - digiKam itself needs tag trees to be saved in IPTC to be able to
> re-create them in digiKam tags hierarchy in database.
> - for "home use" you want to tag your pictures on topics to sort and
> quickly find them again
> I think this is very well implemented now and once its completely polished
> these needs are met perfectly.
> b) "professional use"
> here tags and IPTC-keywords are two completely different things. To
> explain:
> *tags* could be:
> - work for customers -> company X -> job Y
> - free work -> models -> Susi
> (this is personal information to organize my archive, but nothing of it
> should go into IPTC - like the real name of the model is important for me,
> but often should not be published and may not appear in the image file)
> while *keywords* could be:
> - emotions -> love -> parent/child (I know "/" cant be in a keyword... :-)
> ) - people -> groups -> families
> (this is "public data" that I want in IPTC)
> My personal approach here is:
> - use digiKam tags for the tags (leaving "Save image tags as 'Keywords'
> tag" unchecked in Metadata settings), which suits perfect for this
> - use the "edit IPTC Metadata" plugin for the IPTC keywords, which is good
> right now for single entries, but not yet for setting metadata in many
> files and also needs some other improvements in regard of using pre-defined
> word lists for consistency of keywording etc.
> My questions to the digiKam team right now are:
> - what is your target audience (target user group)?


> - if both groups ("home use" and "professional") are targeted, is there
> already a concrete plan about future developments in this regard? If so, is
> this plan public and can I find it somewhere?

We have draft for future release where we post all important ideas todo. It in 
digiKam wiki, shared between me and Marcel, but, there is no plan/idea about 
the home rules of Tags->IPTC keywords

For informations, the current (and uncomplete) development draft is here :


> (I have some ideas, but I don't want to make unnecessary noise by throwing
> in thoughts about things that have already been discussed and decided by
> people who know better than I do)
> Let me know.

Well, the problem is to store in IPTC keywords the Tags _name_ and not the 
Tags _path_. Right ?

For example :

City/Places/NotreDame ==> NotreDame

Ideas :

* Using IPTC "Supplemental Categories" to store Tags Names. There is no 
limitation about how many Sup. Cat. can be stored in Pictures, but each field 
is limited to 32 characters (this is a limitation of IPTC not digiKam).

Problem is than "Supplemental Categories" is depreciate on IPTC draftand is 
not supported by next generation of IPTC draft used into XMP metadata 
(Adobe). This point is important for the future.

* Using IPTC "Subjects" : This is another way to store Tags Names. There is no 
limitation about how many Subject can be stored in Pictures, but each field 
is limited to 236 characters (this is a limitation of IPTC not digiKam).

IPTC Subjects use a complex format. It's not a simple words to write like  
Keywords or supplemental Categories.

For more dtails, look page 31 of IPTC draft :


* Using a dedicaced IPTC tags (there is 20 free for use IPTC tags normally). I 
have never tried to use this way. It's normally depreciate to do it, for 
compatibility issue between photo management program.

* Provide a new batch tool used to export pictures with the right Tags 
information stored in IPTC keywords : the Tags Path _or_ the Tags Name.


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