Photos: How to Move a Master-Version Pair between Photos Libraries

If we want to move a photo to another library, we usually want a lossless move, which means that we want to be able to move the edited version and the original image as a pair, and also preserve the metadata.

If we have many photos to move, the only way to do that is using iCloud Photo Library - Notes on Merging Photos Libraries

But if we have to move just one or two photos, iCloud Photo Library would be overkill, if we are not using it anyway.

If you only want to move a single photo, you can transfer it as a master-version pair with the External Editors extension.

• Export the original photo with "File > Export > Export unmodified original" and use the option "Export IPTC as XMP" to save the metadata in a sidecar file.
• Export the edited version as a JPEG in high quality with "File > Export > Export 1 photo"

Now you have a pair of the original Master and an edited version on your Disk and can import them to Photos plus the saved IPTC metadata in the sidecar file.

1. If the original is a RAW file, you can simply import the pair of orginal and edited version together to the other library and Photos will treat it as a RAW&JPEG pair and stack the two photos as a RAW&JPEG pair and you are done. You can easily switch between the edited version and the RAW file in Edit Mode with the command "Image > Use RAW as Original" or "Image > Use JPEG as Original".
2. If the original is not a RAW file, import only the original to the other library, then open the original in Edit Mode and use the External Editors extension (it is available at the AppStore for a small fee). In External Editors click "Choose File" below "Replace with image from disk". In the File Chooser dialog select the JPEG of the edited version and click "Done", then "Save Changes". Now the JPEG will be used as the edited version, but you can still revert to the original. It will be as if you had used an external editor on the photo.

As to the IPTC sidecar: The sidecar files are currently having an annoying bug. The date is transferred correctly, but not the time. Photos on High Sierra is reading the time always as 00:00:00.

Therefore I would not use the sidecar file with a RAW&JPEG pair. If you import the photos as a pair (method 1), do not export the sidecar file. The JPEG version will keep all metadata and you can see them in Photos, if you are switching to the JPEG as the original.

This user tip was generated from the following discussion: Migrating Photos Between Libraries