Today’s Question: Will future (post-Lightroom) versions of other software recognize and honor the metadata in sidecar (XMP) files for photos that were optimized in the Lightroom Classic Develop module or in Adobe Bridge?
Tim’s Quick Answer: Metadata that is included as part of an existing metadata standard can be preserved and recognized by other software beyond Lightroom Classic. However, most of the adjustment settings would likely be lost in this type of scenario.
More Detail: Many of the metadata fields you might update in Lightroom Classic represent fields from established metadata standards. This includes such things as keywords, star ratings, and other common metadata values.
Other metadata values you can update in Lightroom Classic represent what are essentially Lightroom-specific features. That includes things such as collections, pick and reject flags, and the adjustments you apply within the Develop module.
For the most part, Lightroom-specific metadata values are not saved to your source image files when you choose to save metadata to the actual image file on your hard drive. However, interestingly enough, the adjustments you apply in the Develop module are saved to the files in this case. So, for example, the XMP sidecar file associated with a proprietary raw capture can contain the settings for the adjustments you applied in the Develop module for each photo.
However, some applications are able to extract certain adjustment settings from the metadata based on the Develop module in Lightroom Classic. For example, if you are using a version of Exposure X from Exposure Software, you can migrate some of your Lightroom Develop adjustments (along with other metadata) using their Lightroom to Exposure Migration Tool. You can learn more about this particular option on the Exposure Software website here:
https://support.exposure.software/hc/en-us/articles/214115047
In general, you should assume that only standard metadata fields will be preserved outside of the context of a Lightroom-based workflow. Even then, that metadata will only be preserved with your source images if you have saved metadata to your photos. This is one of the reasons I recommend turning on the “Automatically write changes into XMP” checkbox on the Metadata tab of the Catalog Settings dialog in Lightroom Classic. However, even with this option enabled, it is important to keep in mind that not all metadata will be preserved. In addition, the metadata from the Develop module would likely not be available to other applications beyond Lightroom, Adobe Bridge, and Adobe Camera Raw (via Photoshop).