XMP Risks


Today’s Question: When it comes to the XMP files you recommend creating to save metadata with RAW captures, does the RAW file still work usefully without it? What damage is done when the XMP gets disconnected from the RAW file?

Tim’s Quick Answer: When an XMP “sidecar” file is created for a RAW capture, it contains metadata that was created after the RAW capture was created, and therefore not included in the actual RAW capture file. Thus, losing the XMP file will take you back to the original RAW capture as it came from the camera, missing only the metadata you updated after the capture.

More Detail: One of the primary purposes of an XMP sidecar file is to enable you to update metadata for a RAW capture without actually altering the RAW capture file. In other words, the RAW capture can be treated as an original that should not be altered, with all updates being performed in a non-destructive way.

In the case of Adobe Camera Raw and Lightroom, for example, most metadata updates along with the adjustment settings you’ve applied to the RAW capture can be stored in an XMP file alongside the RAW capture. The XMP file will have the same base filename as the RAW capture that it relates to.

In Lightroom your metadata updates and Develop settings are not written to an XMP sidecar file by default. Rather, those updates are only saved within the Lightroom catalog. However, you can enable an option in the Catalog Settings dialog to also automatically write updates to an XMP sidecar file for your RAW captures.

The whole point of an XMP file is to leave the original RAW capture untouched. Thus, if you lost the XMP file for any reason without losing the RAW file, that RAW file would still be intact and could be processed without difficulty. You would lose metadata updates from the XMP file, although if you are using Lightroom that would not be an issue because the updates would still be stored within the Lightroom catalog. But ultimately the most important file is the original RAW capture, and it is certainly possible to continue working with that RAW file even if the associated XMP file were lost.