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Reference Formats

DNG

DNG is Adobe's open, publicly documented raw image format, designed as a vendor-neutral archival container for unprocessed sensor data from any digital camera.

Extension

.dng

Full name

Digital Negative

Introduced

September 27, 2004

Vendor

Adobe

What is inside the container

DNG is built on the TIFF/EP standard and can store either the camera's original raw sensor data or a converted, demosaiced linear image, alongside camera profiles, lens correction data, and edit instructions. It carries EXIF, IPTC, and XMP metadata natively and always includes an embedded preview, which makes thumbnailing and search indexing far more predictable than with proprietary raw formats. Because the specification is published and royalty-free, DNG decoders do not depend on reverse engineering.

How to open it

Windows / macOS Adobe Photoshop, Lightroom Classic/CC, and Adobe Camera Raw, which read DNG natively without an update
macOS / iOS Preview.app, Photos, and Apple's native RAW pipeline (Core Image), which support DNG out of the box
Cross-platform, open source RawTherapee, darktable, and GIMP with a raw plugin, all built on libraw
Command line / batch conversion Adobe DNG Converter, free, used to normalize other cameras' raw files into DNG

For archives

DNG is itself the recommended long-term archival target for raw photography in a DAM. Because the specification is open and published, decoding does not depend on any single vendor staying in business, which is why institutions such as the Library of Congress list DNG as a suggested format for raw camera images rather than any manufacturer's proprietary variant.

Adobe launched DNG on September 27, 2004, alongside the first version of the DNG specification and a free conversion utility. The motivation was straightforward: every camera manufacturer had its own closed raw format, with no guarantee any of them would still be readable in ten or twenty years. Adobe’s answer was a single, documented, TIFF/EP-based container that could hold the full unprocessed sensor data from essentially any digital camera, alongside standard metadata fields.

Because the DNG spec is public, support for it does not rely on any one company reverse-engineering another’s format. Photoshop, Lightroom, Apple’s Photos and Preview, and open-source tools such as RawTherapee and darktable all read DNG the same way, and the format mandates an embedded preview image, which makes generating consistent thumbnails and proxies far more reliable than with most proprietary raw formats.

This is why DNG shows up repeatedly through this reference series as the recommended endpoint for RAW ingestion: a DAM that standardizes on DNG for its raw masters, or at minimum generates a DNG derivative for every proprietary raw file it stores, removes the single biggest long-term risk in raw photo archiving — decoder support disappearing when a manufacturer discontinues a camera line or exits the market.

Frequently asked

Why is DNG recommended as the DAM archival target for raw photography?

Because its specification is open, published, and royalty-free, so decoding does not depend on any single vendor staying in business; institutions such as the Library of Congress list DNG as a suggested format for raw camera images for exactly this reason.

What metadata does DNG support natively?

EXIF, IPTC, and XMP metadata natively, and it always includes an embedded preview, which makes thumbnailing and search indexing far more predictable than with proprietary raw formats.

Can DNG store either the original sensor data or a processed image?

Yes. DNG can hold either the camera's original raw sensor data or a converted, demosaiced linear image, along with camera profiles, lens correction data, and edit instructions.

What is DNG built on structurally?

The TIFF/EP standard, the same base standard underlying several proprietary vendor raw formats, but with a published, open specification.

Do DNG decoders depend on reverse engineering, unlike most vendor RAW formats?

No. Because the specification is published and royalty-free, DNG decoders do not depend on reverse engineering the way RW2, RAF, X3F, and most proprietary raw formats do.

What free tool converts other cameras' proprietary raw files into DNG?

Adobe DNG Converter, a free command-line/batch conversion tool used to normalize raw files from many manufacturers into a single archival DNG standard.

Does DNG work outside the Adobe ecosystem?

Yes. Preview.app, Photos, and Apple's native RAW pipeline via Core Image on macOS/iOS support DNG out of the box, and open-source tools like RawTherapee, darktable, and GIMP with a raw plugin also read it through libraw.

When and by whom was DNG introduced?

Adobe introduced DNG on September 27, 2004, as an attempted open, unifying standard for the fragmented world of proprietary camera raw formats.

Sources