DWU2 Loc: Phoenix Arizona area

I've been using Lightroom for about six years. Throughout that time, I've configured the catalog settings to write edits to the catalog, and NOT create .XMP sidecar files. I noticed today that, in my photo directories, there are about 400 .xmp files There's about 35,000 photos from those same years, so only about 1% of the photos have .xmp files.

Recently, I've been using Photoshop a lot more. I'm assuming the .xmp's come about from that.
Usually, I start with a photo in LR, and round trip in and out of Photoshop. Sometimes, when doing learning exercises in Photoshop, I've opened photos directly from PS, edited, and saved them in a Photoshop training file.

So, the existence of the 400 .xmp files raises a few questions:

1. Does round-tripping from LR cause an .xmp file to be created?
2. Does directly accessing a file from PS (without round tripping) cause an .XMP file to be created?
3. If "yes" on either of the above, is it because edits were performed in ACR?
4. Is there any value to keeping these .XMP files?
5. Is there a setting within PS that controls the creation of .XMP files?

bsprague Loc: Lacey, WA, USA

1. Does round-tripping from LR cause an .xmp file to be created?
No.

2. Does directly accessing a file from PS (without round tripping) cause an .XMP file to be created?
Yes. Opening a RAW file with Photoshop causes ACR to open first. When you finish with ACR, an XMP is created to remember any edits. The XMP takes the place of what the Lightroom catalog does.

3. If "yes" on either of the above, is it because edits were performed in ACR?
Yes.

4. Is there any value to keeping these .XMP files?
Yes. Any ACR editing is stored in the XMP. Deleting the XMP deletes your work and effort. To go further, you can't edit RAW files. They are RAW data, not interpreted data in a JPEG. If you do ANYTHING to a RAW file, the results have to be stored somewhere.

5. Is there a setting within PS that controls the creation of .XMP files?
No. If you elect to work with RAW files you have to have somewhere to store the intrepretation of the RAW data. In the Adobe system it is either the Lightroom catalog or the XMP files.

My procedures include having the XMP option turned on in Lightroom. There are two benefits. One is that if I open the RAW file in some other software, the Lightroom adjustments are read. For example, if I use Adobe Premiere Elements to create slide shows or include stills in a video, I can work directly with the RAW files without making an intermediary, compressed and lossy JPEG. The second advantage is that if my Lightroom catalog gets totally wrecked, the XMP files are a copy of the Develop module work. If I had to start over with an entirely new catalog, the XMP files would be read on import and all adjustments would show in the Develop module.

DWU2 Loc: Phoenix Arizona area

bsprague - thank you for your thoughtful remarks.

A followup question - If I open a RAW file in PS, make some changes in ACR, then move into PS proper, make further changes, then save the result as a TIF or PSD, is there any benefit to saving the .XMP in that case?

bsprague Loc: Lacey, WA, USA

Yes. If you take the TIFF down an adjustment path you don't like, the XMP makes a do over easier. Secondly, the XMP lets you import the RAW into Lightroom and keep the ACR edits.

The XMPs are tiny and do no harm. They only have benefits. Why do you want to get rid of them?

DWU2 Loc: Phoenix Arizona area

Just wanting to keep things neat. One day, I may not be here anymore, and someone else may have to figure out what's what among the photos.

bsprague Loc: Lacey, WA, USA

That makes no sense to me. If someone goes through my photos why would the not want to see the development/editing work I did?

jeep_daddy Loc: Prescott AZ

You should let LR create the XMP files and stop saving your changes in the catalog. If your catalog becomes corrupt, you lose all your edits. If you have XMP's, you never lose your edits and when you use ACR from Bridge in PS, the edits are there in the XMP.

DWU2 Loc: Phoenix Arizona area

I think this is a topic where well-informed people could still disagree. There are trade-offs involved, as is always the case in photography. Here's a couple of interesting articles on the issue: https://www.lightroomqueen.com/community/threads/lightroom-catalogue-backup-vs-xmp-files.21431/
https://lightroomkillertips.com/writing-xmp-files-shouldnt/

DirtFarmer Loc: Escaped from the NYC area, back to MA

I have LR write .xmp files and I keep them. They're small and don't take up much disk space.

My folder structure is set up so that a particular subject has a folder with a meaningful name (e.g. "Suzie's Birthday"), as a subfolder of [year]. The primary folder then has a subfolder /RAW, which holds both the .nef and the .xmp files (I shoot Nikon). The edited results are made into jpgs and stored in the primary folder. So someone who comes after me has a folder (e.g. /photos/year/Suzie's Birthday) with all the interesting stuff and a subfolder (/photos/year/Suzie's Birthday/RAW) with the stuff they will not be interested in, both .nef and .xmp.

While LR is superb at organizing my stuff (as long as I am good about keywording and putting things in collections and sets), none of my family knows how to use LR, so the second level organization using folder names is essential to preserving my family photos (and others, if anyone's interest there).

davefales Loc: Virginia

You can adjust your ACR settings in the Preferences, the multiple line tool at the top left, to not save as .xmp/sidecar files.

dino21 Loc: McAllen, TX

Your setup as far as keeping your photos sounds like what I want to do. So you make jpegs or tif files from the raw files and then keep the raw files seperate? My mind is going with my old age and sometimes it takes me along time to figure things out. sorry

Mike in S TX