This information applies to versions 5 and newer
Since version 5, DxO PhotoLab reads rating data from .xmp files and no longer from .dop files.
This change makes it easier to work with third-party applications (such as Adobe Lightroom) to ensure the consistency of image ratings.
To ensure that DxO PhotoLab takes the proper data into account, you can either activate the “Always synchronize” option in the “Metadata synchronization” section under the “General” tab in the Preferences, or you can manually read/write metadata from .xmp files.
The table below (click on it to enlarge) sums up how DxO PhotoLab handles data from sidecar files:
Note: DxO PhotoLab also writes all data (correction settings, attributes, and metadata) into its own database for both Master and Virtual Copy(ies).
When synchronization is off, all data is read from the database. Users must manually import data from files if they want to update database data.
When synchronization is on, the data is prioritized by the most recent changes. This means that if the user has updated metadata information in a third-party application, DxO PhotoLab will read it and overwrite the existing data in the database (as the third-party data will be considered as more recent).