File extension

.dng

Digital Negative (DNG)

.dng files are Digital Negative (DNG) images: an open, TIFF-based raw image format from Adobe intended as a common alternative to proprietary camera raw formats.

Known meanings

Formats and reference material for .dng

Digital Negative (DNG)

TIFF/EP-based raw image format with standardized metadata for camera sensor data

  • 2d-graphics
  • Adobe
Open link

Details

Format notes

DNG

Digital Negative (DNG) is a raw image file format introduced by Adobe in

  1. Camera manufacturers each use their own raw formats, such as CR2, NEF, or ARW, which often lack public documentation. DNG was created as a publicly documented format that can hold raw sensor data from many cameras along with the information needed to interpret it. Adobe publishes the specification and allows implementation without license fees.

Technical Structure

DNG is based on the TIFF 6.0 and TIFF/EP structures. A file starts with a TIFF header (II*\0 for little-endian or MM\0* for big-endian), and its image file directories use standard TIFF tags plus DNG-specific tags, such as DNGVersion. The raw data is usually a CFA (Bayer-style) mosaic, though the format also supports “linear” DNG with demosaiced data. DNG tags describe color matrices, black and white levels, white balance, camera calibration, and optional opcodes for lens corrections. A DNG file can also contain embedded previews, Exif and XMP metadata, and optionally the original proprietary raw file. Raw data may be uncompressed, losslessly compressed, or lossy compressed.

Adoption

DNG is the native format of some cameras and of many smartphone apps, and Lightroom and Photoshop can convert other raw formats to DNG. Open tools such as LibRaw-based applications and darktable can read it. The specification has been revised several times, so older software may not read files that use newer features.

Preservation Notes

DNG is often chosen for archiving because its documentation is public and it avoids dependence on camera-specific formats. Conversion can discard manufacturer-specific metadata unless the original raw file is embedded, so record what conversion tool and DNG version were used. Because DNG is TIFF-based, parsers should check IFD offsets and tag counts.

Further Reading

  • Library of Congress format description: https://www.loc.gov/preservation/digital/formats/fdd/fdd000188.shtml