Just a couple of thoughts about Lightroom.
a. Lightroom does not utilise xmp files by default, Lightroom reads and writes to the Catalog File (a data base file) so the concept is that the info is in the Catalog. This is different than when you work with Photoshop/ Adobe Camera Raw where info is stored in xmp files (sidecar files or in the file header of dng, jpeg and tiff files).
b. Lightroom will read xmp data from files at the import stage and store the data in the Catalog file, if xmp data is subsequently changed outside of Lightroom the Lightroom Catalog will not automatically be changed, however there is an option to read the data from the file to make changes to the Catalog. This can cause some confusion since work done in Lightroom will be changed or undone.
c. There is also an option in Lightroom Preferences to also have xmp data written to the files, however this does not alter the fact that Lightroom is reading and writing to the Catalog file. This option of writing to xmp gives an alternate recovery option of your work in the event your Catalog file gets lost or corrupted.
Please provide additional info as to what exactly you are trying to achieve, Its always the preferred option to work with one Catalog in Lightroom
Better to have
One Catalog ( database).
Sub divide using multiple Collections.
Use keywords to help search processes.
You cannot search and sync across multiple Catalogs, i.e. Lightroom can only have one Catalog open at any time.
Hi thanks for the info. I would like to know why the finder information is so weird. Where is the date added coming from? It has no apparent relation to when the file was added to my system. I presume the data on finder is created by Lightroom when it added my files to the disk and to the catalog.
Since I have Lightroom setup with .xmp, I was planning to use the dates on the files to identify the changed .xmp's. I presumed I could download them to my desktop and re-sync the catalog. Would this work?
Don't do this via xmp. Some items are never written to .xmp.
Do this via the command sequence as follows:
- On the laptop computer, in Lightroom, select the desired photos and then use the menu command File->Export as Catalog. If the photos are not on the desktop computer, check the box that says "Include Negatives"
- Copy all files created to the desktop computer
- On the desktop computer, use the command File->Import from Another Catalog and point Lightroom to the catalog file just transferred from the laptop.
This leaves the question of how to identify the recently edited photos. Create a smart collection with the criterion that the Edit Date is greater than YYYY-MM-DD, where of course that is the date of interest.
As an after thought, what if I create .dng's of the modified objects in the smart collection and then add the objects to my desktop Lightroom catalog? After adding the the dng's I could simply delete the duplicate raw file. Is this reasonable?
You are making your life more complicated. I suppose if you really really really really really really want to have DNG on the laptop computer and then RAWs on the other computer, it's extra work, and since I don't really know the entirety of your workflow, there may be glitches ... and using DNGs for this specific purpose of transferring photos from one Lightroom catalog on your laptop to the other Lightroom catalog on your desktop doesn't seem to have any benefits I can think of.
DNG files do not overcome the drawback I mentioned that XMP does not contain everything, the only way to overcome that is to use the catalog approach I explained.
I'm sorry I was not clear. The changes are in my laptop. I would create the dng 's there then transfer it to my desktop. Add it to my desktop catalog then remove all the raw and xmp files corresponding to the dng. My impression was a dng has all the changes within it.
This is not my workflow but a work around to get my changes into my real repository.
You are making extra work for yourself.
And some of your information will NOT get written to DNG or to XMP files.
The best and most complete way is to export as catalog on one computer, and import from another catalog on the 2nd computer.
Thanks for your help. I tried to set the discussion correct but could not find the action.