Darktable - working on two computers with one hard drive / synchronise ALL EDITS

[Drazen-01]

I have to try here since this topic looks like does not have a good solution…
With Darktable, I am working in parallel with two computers:

• PC/Windows: Darktable 4.8.1 to work “at home” and
• Macbook M3 Pro: Darktable 4.8.0 as “on the way” device

I hold my photos on an external 2TB SSD and plug this SSD to one or another computer when I need.
The problem is the SYNCHRONISATION of the LATEST STATUS I worked on. In the Darktable, I went to preferences > storage > look for updated XMP files on startup… there, I sat an “OK”.
Since I have worked on the MAC on my files e.g. during a trip, then I want to proceed WITH THE SAME CHANGES further on my home PC. I plug in the SSD and get 4 possibilities to synchronise the changes in my workflow:

1. Keep the XMP edit
2. Keep the database edit
3. Keep the newest edit
4. Keep the oldest edit
   Let’s skip the last one/oldest edit. I want the most recent edits.
   So, my question is: If I want to keep Darktable edits (like contrast, crop, colour, lens correction, etc.), but also my photo rating in stars and colours, metadata changes, but also if I have duplicated or deleted some edits/photos in Darktable (there will be then more or less XMP-files near my DNG if I want to make few versions of one photo) … so well, I want to have ALL LAST CHANGES transferred into the other computer/Darktable.
   I have got a hint from a dear YouTuber, but still cannot synchronise ALL EDITS – no matter if I chose: Keep the XMP edit, Keep the database edit or Keep the newest edit.
   I get/synchronise the last changes, but duplicates or deleted duplicates or photo evaluation are not always synchronised. I can than “remove the film roll” and again “add to library” this filmroll again. This action brings all edits into the Darktable, but I cannot believe this is the way of synchronising the libraries.
   Can this problem be solved?
   Can we soon expect a solution (e.g. upgrade), so this will be possible?

[ptilopteri]

* Drazen-01 ***@***.***> [01-20-25 14:21]:

I have to try here since this topic looks like does not have a good solution… With Darktable, I am working in parallel with two computers: - PC/Windows: Darktable 4.8.1 to work “at home” and - Macbook M3 Pro: Darktable 4.8.0 as “on the way” device I hold my photos on an external 2TB SSD and plug this SSD to one or another computer when I need. The problem is the SYNCHRONISATION of the LATEST STATUS I worked on. In the Darktable, I went to preferences > storage > look for updated XMP files on startup… there, I sat an “OK”. Since I have worked on the MAC on my files e.g. during a trip, then I want to proceed WITH THE SAME CHANGES further on my home PC. I plug in the SSD and get 4 possibilities to synchronise the changes in my workflow: 1. Keep the XMP edit 2. Keep the database edit 3. Keep the newest edit 4. Keep the oldest edit Let’s skip the last one/oldest edit. I want the most recent edits. So, my question is: If I want to keep Darktable edits (like contrast, crop, colour, lens correction, etc.), but also my photo rating in stars and colours, metadata changes, but also if I have duplicated or deleted some edits/photos in Darktable (there will be then more or less XMP-files near my DNG if I want to make few versions of one photo) … so well, I want to have ALL LAST CHANGES transferred into the other computer/Darktable. I have got a hint from a dear YouTuber, but still cannot synchronise ALL EDITS – no matter if I chose: Keep the XMP edit, Keep the database edit or Keep the newest edit. I get/synchronise the last changes, but duplicates or deleted duplicates or photo evaluation are not always synchronised. I can than “remove the film roll” and again “add to library” this filmroll again. This action brings all edits into the Darktable, but I cannot believe this is the way of synchronising the libraries. Can this problem be solved? Can we soon expect a solution (e.g. upgrade), so this will be possible?

I work across multiple computers with one library. I work photos until I am satisfied, using "darktable --library :memory:" and ONLY import into the library when I am finished working.

…

-- (paka)Patrick Shanahan Plainfield, Indiana, USA @ptilopteri facebook/ptilopteri Photos: http://wahoo.no-ip.org/piwigo paka @ IRCnet oftc

[wpferguson]

@Drazen-01 can you list how you want each specific situation (newer xmp, new duplicate, missing xmp (and image?), etc.) to be handled (rather than leaving it up to us to guess).

[Drazen-01]

I am sorry, am no experienced programmer, but just a happy user of Darktable.
I will try to specify….
I work on home computer (PC) and go for a week trip. There I work on 300 photos on my notebook (Macbook), but 700 photos remained to be done at home. So, I need to proceed on these photos retaining all changes I have done on the Mac. This can be also the other way round – my work from home (PC) shall be transferred to the Macbook if I can work during my holidays or trips. All photos are on the external SSD which is always with me.
What I need to keep:
All changes I have done:
• colour management
• base corrections (Exposure etc.)
• other corrections like haze, lens correct
• effects
• (all what darkroom offers)

• then, also metadata, all what the changes may consists of
• my evaluation of the photos in stars and colours
• I sometimes delete some photos and
• sometimes work on two or more versions to decide later which photo edit to choose and for which purpose. This shall also be transferred, so I always have the latest status.
Unplugging SSD is easy. My idea is to have automatic update (e.g. a choice like “keep all edits and database structure”… but, maybe my wording is wrong here).
I have a regular backup disc, so, if I messed up something, the backup will help.
For me is important that the last work shall be the most relevant one and all last edits shall be taken to the other computer.
I hope I have explained it better now. Did I?

[gi-man]

Are you importing all 1000 (300 you worked and the 700 remaining) to the laptop?

I don't suggest your workflow is a good one since it could have issues, but why not place all your eggs in one basket? Invoke darktable with the configdir flag pointing the config to be a folder within your sdd drive. Also invoke the cache dir if you have the space.

https://docs.darktable.org/usermanual/4.6/en/special-topics/program-invocation/darktable/

[kofa73]

Darktable does not monitor imported directories. The files are imported once.
To remove entries from the database (darktable's catalog) that correspond to photos you have deleted, you can use purge_non_existing_images.sh . You'll have to get bash for Windows. Or there is https://github.com/darktable-org/lua-scripts/blob/master/contrib/dbmaint.lua (see https://github.com/darktable-org/luadocs/blob/master/content/lua.scripts.manual/scripts/contrib/dbmaint.md) (@wpferguson , is it intentional that there is no link to this script at https://github.com/darktable-org/lua-scripts?tab=readme-ov-file#contributed-scripts ?).
For new duplicates, just do an import.

[wpferguson]

is it intentional that there is no link to this script at https://github.com/darktable-org/lua-scripts?tab=readme-ov-file#contributed-scripts

No, but...

For a long time the README was the only form of documentation that we had. Now we have the lua docs. For the last month or so I've been trying to figure out what I should do with the README, since keeping 2 sets of documentation up to date (and agreeing with each other) is something that I'm not doing well 😦

My thought at this point is to remove most of the content from the README and put links to the appropriate places in the lua docs. I'm listening if you have any ideas.

[kofa73]

I know your pain ('duplication is the root of all evil'). I think referencing the docs from the readme is a good idea.

[Drazen-01]

Just to check if I did it right - the question as user of Darktable: Was my need clearly described?

[gi-man]

Just to check if I did it right - the question as user of Darktable: Was my need clearly described?

No it was not clear to me. I had a follow up question and a proposed solution for you to try.

[wpferguson]

Yes, we understand what you want. Now we just need to figure it out.

[todd-prior]

Just to check if I did it right - the question as user of Darktable: Was my need clearly described?

Could you do a version of what @wpferguson suggested...can you have 2 databases. Bill just edits his photo with the session based virtual database ie the memory option and then imports when he is finished. You say you always have the drive and always have the images..you just plug this in to one PC or the other....can you just create a database on that SSD and run DT on each machine to use that common database by use a commandline option and specify the database/library location... You could call that mobile or travel or whatever...when you are done or have a batch that don't need this anymore you can transfer the images and edits to your final or main storage location which could be using a different database perhaps master database called main.... Its a version of how some people work with multiple databases for personal and various projects that they might have and keep things separated.... I'm not sure if that would work for you but you might be able to do something like that...

[Drazen-01]

Let's see... maybe I misunderstand due to my limited knowledge about software...

I have all my photos in a folder on my SSD (mobile storage). I work only with this SSD and just have my backups extra on another disc, but do not work with these (only backup). I am not transferring any files to any local computer - I am working only on the mobile SSD.

My both computers recognise the source (is this meant under "use a commandline option and specify the database/library location"), but not all of the changes can be transferred - only if I delete the film roll on the computer I want to switch to. Than import the film roll again. This is not an elegant procedure though.

What I can do, I can make ALL changes on a film roll on one computer and, when ready, than transfer to another computer and print or save final photos. But, I want to work on both - since I often switch from home to mobile work. This is my problem. Often my film rolls are partly finished. So, I need to proceed on another computer to finish this film roll.

Do I miss the point?

[wpferguson]

Are both computers using the same operating system and is the SSD mounted at the same mount point?

[Drazen-01]

The Home computer is PC, Windows 10
The Portable Computer is Macbook, macOS Sonoma 14.16.1

SSD is on each computer mounted always on the same point, but due to working on two different computers, in this case, when changing computers on different points since different computers. I use the UCB-A/C cable.

[kofa73]

@wpferguson : I have the impression the DB is not shared, so different paths cause no issues.