How Photolab changes RAW file and sidecar from Photoshop

If I have a folder of RAW files that have been processed with Photoshop (with accompanied sidecar files), what happens to the RAW file and the Photoshop sidecar if I open the RAW file in Photolab? What happens to the RAW file and the Photoshop sidecar if I process the file in Photolab?

Do you open the raw file in PS as you write or do you export it from PL?

Opening a raw in PS invokes Adobe Camera Raw.
The .dop sidecar will be ignored.
PS will then save your edits in the output file.

Exporting from PL to PS enables you to transfer PL edits to PS. From there on, things work as above.

I’m not talking about importing or exporting files. If I have a RAW file processed with Photoshop in the past. It will have a sidecar associated with it. What happens to the Photoshop sidecar if I open the RAW file in Photolab? (If I go back and what to reopen the RAW file with Photoshop, will I be able to do that? Will the sidecar have been deleted?

This is what I tried and what I got:

  1. Open a .cr2 file in photoshop
  2. Invert the tone curve
  3. Quit PS while saving the file

What I got:

  1. a .xmp sidecar file
  2. a .psd output file

DPL

  1. Open the folder that contains the .psd file and its sidecar
  2. DPL does not even show the .psd file. It ignores the settings in the .xmp too.

Is the .cr2 file in the same folder as the .psd file? I thought he .xmp files are supposed to be interoperable between PS/LR and PL. That is, if you open the .cr2 file in PL, the associated .xmp should be readable, at least for metadata.

Yes, @Evildad, the .psd is in the same folder as the .cr2! DPL ignores development settings from xmp sidecars. Only the keywords transfer to the DPL database.