Post by Tobias EllinghausYou can't. No idea where that idea comes from.
The difference is quite simple: A "folder" is something on your system level,
inside dt we call it a "filmroll". That's it. In general it's a 1:1 mapping,
however, you can copy images to a folder after importing it or remove imported
images inb dt while keeping them on the disk. So there may be cases where the
content of folder and filmroll differ, thus we call them differently.
For me there is a 1:1 correspondence, i.e. I don't add pictures to a folder
that has previously been imported into darktable without importing them and
I don't delete pictures from under darktable. If you add pictures to a
folder and re-import the folder darktable seems to be clever enough to
import the extras - at least in the sense it does not lose the edits on the
ones originally imported.
When I first started with darktable I wasn't sure what to make of "film
roll" as an organisational tool. I came to the conclusion it was simply a
batch of picture imported together in the same way a roll of film would be
developed at one time and that roll may correspond to something in real
life like an event, a studio shoot, a holiday etc. or it may just be a bit
of a mix.
In practice, I tend to import pictures frequently so much more than would
be the case with film there is something to tie the pictures together,
though just what that is varies.
Prior to darktable I used a couple of picture management applications both
of which, as far as I remember, encouraged the use of tags under a tree for
which the top level tags were "Events", "People" and "Places". I don't
always add an "event" tag but I do often use the other two and tags can be
used to have a virtual collection that spans film rolls so, for example, if
you tag people you can then find all the photos down the years that feature
the same person or with place tags you can compare the same location in the
spring, summer and autumn even if these are in different film rolls.
Tagging is really as powerful as you want to make it and how much effort
you want to put in.