What Is an XMP File? Lightroom Sidecars & Presets Explained
An .xmp file is a small text file that travels alongside a photo and carries everything about it that isn't pixels: editing instructions, ratings, keywords, copyright. XMP (Extensible Metadata Platform) is an Adobe-created, XML-based open standard.
For photographers, XMP matters most in two forms: the sidecar file that stores your Lightroom/Camera Raw edits next to a RAW file, and the preset file that packages a reusable look.
Why sidecars exist: non-destructive editing
RAW files are treated as read-only negatives — an editor never alters them. Instead, every slider you move is written as an instruction: “Exposure +0.5, Shadows +30, this tone curve, that mask.” Those instructions live in a catalog or in an .xmp sidecar named like the photo (IMG_4021.CR3 → IMG_4021.xmp).
The payoff: edits are reversible forever, and sharing the tiny sidecar shares the entire edit. Anyone with the same RAW can reproduce — or remix — your grade exactly.
What's actually inside
Open an .xmp in a text editor and you'll find XML with namespaced attributes. The interesting ones for editing carry the crs: prefix (Camera Raw Settings): crs:Exposure2012, crs:Contrast2012, tone curve point lists, per-color HSL adjustments, split toning and color grading values, and — since Lightroom's masking update — complete descriptions of radial, gradient, brush and AI masks with their local corrections.
This is exactly what RawCut parses in your browser: drop an .xmp next to a photo and the full recipe — every slider, curve and mask — becomes visible, learnable and exportable.
XMP presets vs. sidecars
A preset .xmp is structurally the same file without a photo attached — just the settings you chose to include. Lightroom stores them in its Settings folder; importing one gives you a reusable starting look. Because presets store instructions rather than baked colors, they stay fully editable — the key difference from a LUT.
Frequently asked questions
Can I delete .xmp files?
If you delete a sidecar, the RAW file survives but the edits described in it are lost (unless they're also in a Lightroom catalog). Keep sidecars with their RAWs when archiving.
How do I get Lightroom to write .xmp sidecars?
Catalog Settings → Metadata → “Automatically write changes into XMP”, or select photos and press Ctrl/Cmd+S to write them on demand.
Does an .xmp file contain the image itself?
No — only metadata and instructions. That's why sidecars are a few kilobytes while RAW files are tens of megabytes.
Drop a photo with its .xmp into the RawCut Inspector and see every slider, curve and mask visualized — then replay the edit step by step.
Inspect an XMP in your browser