The DNG file (.dng)

DNG is a raw photo format, like Canon's CR3 or Nikon's NEF, with one big difference: it isn't tied to a camera maker. Adobe published the specification in September 2004 as an open, documented alternative to the growing number of proprietary raw formats, and has updated it ever since; version 1.7.1.0 (September 2023) is current. In March 2026 it also became an international standard, ISO 12234-4, part of the same series as TIFF/EP (ISO 12234-2), on which DNG is built.

DNG files come from two places:

• Cameras and phones that write DNG themselves. Adobe lists Leica, Pentax, Ricoh, Casio and Samsung among camera makers with direct DNG support. iPhone Pro models save Apple ProRAW as DNG, and Android's camera API has had a class for writing DNG files (DngCreator) since Android 5.0, so many Android camera apps offer DNG.
• Conversion. Adobe's free DNG Converter for Windows and macOS turns the raw files of hundreds of camera models into DNG. Lightroom can do the same on import, and other tools can export DNG too.

Like any raw file, a DNG holds what the sensor recorded, before the camera decided on white balance, contrast, sharpening and colour. It needs to be developed in raw software, which is why it looks flatter or different from the JPEG the camera or phone would have made.

Nearly all camera sensors see in one colour per pixel. A grid of coloured filters, usually red, green and blue in a 2 × 2 Bayer pattern, sits on top of the sensor. A raw file stores those single-colour values, typically at 12 or 14 bits per pixel: 4,096 or 16,384 levels, against 256 in an ordinary JPEG.

To turn that into a photo, raw software has to demosaic (estimate the two missing colours for every pixel), apply the white balance, convert the camera's colours into a standard colour space, and apply a tone curve. Each program does these steps its own way, so the same DNG can look different in Lightroom, darktable and Apple Photos. A raw image shown with a neutral starting point looks flat and dull next to the camera's JPEG, which has contrast and saturation added.

What DNG adds is a way to carry the information needed for those steps in the file itself: colour matrices and camera profiles, the white balance at capture, the black and white levels, lens corrections stored as opcodes (small processing instructions such as distortion or vignetting correction), and the camera maker's private data, preserved as a block. A reader that has never heard of the camera can still develop the image.

• Lossless (the usual kind). The raw data compressed with lossless JPEG, the same old JPEG mode many camera formats use. Converting a camera's raw file to lossless DNG keeps every value.
• Lossy DNG. Since version 1.4, a DNG can store raw data with lossy compression. The files are much smaller and still hold high-bit-depth, unprocessed data, but some fine detail is discarded and can't be recovered.
• JPEG XL. DNG 1.7 added JPEG XL, a newer codec that can compress either losslessly or lossily. Software that predates DNG 1.7 can't decode these files.
• Linear DNG. The data has already been demosaiced into three colours per pixel (PhotometricInterpretation 34892). It's still high-bit-depth data without white balance or a tone curve applied, but the demosaicing can no longer be redone with a better method, and with three values per pixel instead of one the files are larger.

When a camera's own raw format is converted, the DNG can also embed the original raw file inside itself, so it can be extracted again later, at the cost of adding the original's full size.

Arguments for converting to DNG: long-term access without depending on one company's raw decoder, colour data carried in the file, and the option of lossy compression. Arguments against: the camera maker's own software, such as Canon's Digital Photo Professional, usually reads only the maker's own formats, some maker-specific details are kept only as private data that other tools ignore, and the conversion is one more step. Many photographers keep the originals and use DNG only where it helps.

• Edit: Adobe Lightroom, Lightroom Classic, Camera Raw (in Photoshop), Capture One, darktable, RawTherapee, DxO PhotoLab and Affinity Photo all develop DNG.
• Just look: on a Mac, Photos and Preview open DNG; Apple's systems include basic DNG support for cameras not on their raw list. On Windows, install Microsoft's free Raw Image Extension (built on LibRaw) for thumbnails in File Explorer and viewing in Photos. iPhones and Android phones open DNG in their gallery apps.
• Make one: run Adobe DNG Converter on a folder of camera raw files. It's free for Windows and macOS and has a command-line mode for batch jobs.
• Export a JPEG: develop the image in any of the editors above, then export. On the command line, darktable-cli photo.dng photo.jpg or rawtherapee-cli -o photo.jpg -c photo.dng.
• Inspect: exiftool -a -G1 photo.dng lists every tag, including the DNG version and compression.

• It looks flat, dark or less colourful than the JPEG. Normal for raw: the camera's or phone's picture style isn't applied. Apply a profile or auto-tone in your editor.
• It changes after a second. The viewer showed the embedded preview first, then rendered the raw data with its own settings. The second version is the raw file as your software develops it.
• A ProRAW photo looks different outside Apple Photos. Apple notes that apps that support DNG can open ProRAW files, but the images may look different. Each app develops the data with its own processing.
• It's huge. Raw files are large; Apple quotes about 25 MB for a 12-megapixel ProRAW photo and about 75 MB at 48 megapixels. Lossy or JPEG XL compression makes DNGs much smaller.
• A converted DNG doesn't open in the camera maker's software. Expected: most makers' apps read only their own raw format. Keep the originals if you need those tools.

A DNG holds the same kinds of metadata as a camera JPEG, often more:

• GPS location, especially in DNGs from phones with location switched on.
• Serial numbers. DNG has a CameraSerialNumber tag, and makers' private data can include lens and body serial numbers that link photos to one camera.
• Names and edits. Artist and copyright fields, and XMP metadata with keywords, ratings and the full list of Lightroom adjustments.
• An embedded original. If the original raw file was embedded, all of its metadata is in there too.

To share a photo, export a JPEG without location data rather than sending the DNG. exiftool -gps:all= photo.dng removes GPS from a DNG if you must send the raw file.