Capture One Session File

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COS files are XML CaptureOne Session files which contain metadata for each image within a CaptureOne session. Capture One is a software for RAW photo editing geared for photography.

Identify it

Extensions	`.cos`
Signatures	`3c3f786d6c2076657273696f6e3d` at byte 0 (Capture One Session File)
PRONOM	`fmt/1857`
Wikidata	`Q118465354`

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Open it

Capture Onereads and writes · proprietary license

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Sources

PRONOM fmt/1857
Wikidata Q118465354

From PRONOM, Wikidata. Updated 2026-10-20.

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