[digiKam-users] How to narrow search based on tags

[Remco Viëtor]

On mercredi 7 avril 2021 19:22:22 CEST trparks1 at gmail.com wrote:
> Hi folks,
> 
> I am a new user trying to tackle a big project organizing personal and
> family photos totaling maybe 100K images.  I had thought I’d mostly
> organize by:  [Date], [Place/Event], [People] (and also maybe photographic
> quality star rating).  I started kicking the tires in Digikam and applied
> tags of Place and People in a sample directory that was already sorted by
> date, but ran into a speed bump when I tried to apply tag filters to narrow
> the selection.  The filter function (right tools bar) seems to apply
> Boolean OR as to what is left in the main display when multiple tags are
> selected and AND is not avaialbe.  I had envisaged being able to narrow
> searches based on these tags rather than expanding them.  E.g If I’m
> looking for shots of Lisa skiing, I don’t want all skiing shots plus all
> Lisa shots.  Is there something I’m missing about the Filters functionality
> or another way to get there?
There is a button next to the checkbox "Images without tags", there you can 
select to combine tags with a Boolean AND. In addition, the left side 'tag' 
tab allows an "OR" selection of tags within the filtered selection.
As the right-hand filtering is persistent, you can switch to "Captions" to 
e.g. add tags.

For more complex selections, there's the left side "Search" tab.
> 
> As background, I’d like to ultimately write the tags or other sortable
> information in each image’s metadata so that sorting is possible
> independent of platform.  So another way of efficiently getting there
> (rather than tags) might be OK too.

Writing metadata to the image files is a configuration option. For raw files, 
this writing is experimental (and perhaps not possible for all formats); some 
think it's a bad idea in principle to write to raw files. 
In addition, there's the possibility to write metadata to sidecar files, 
useful when dealing with raw files and external programs (e.g. darktable, a 
raw developer, reads Digikam sidecar files, which allows import of e.g. tags 
added through Digikam into darktable).

Remco