Digital negative
 |
|
| Filename extension | .dng |
|---|---|
| Developed by | Adobe Systems |
| Initial release | September 27, 2004 |
| Latest release |
1.4.0.0
(September 2012) |
| Type of format | raw image format |
| Container for | Metadata may be embedded in XMP, Exif or IPTC formats. |
| Extended from | TIFF/EP |
| Open format? | Yes |
| Website | helpx |
Digital Negative (DNG) is a patented, open, non-free lossless raw image format written by Adobe used for digital photography. It was launched on September 27, 2004. The launch was accompanied by the first version of the DNG specification, plus various products, including a free-of-charge DNG converter utility. All Adobe photo manipulation software (such as Adobe Photoshop and Adobe Lightroom) released since the launch supports DNG.
DNG is based on the TIFF/EP standard format, and mandates significant use of metadata. Use of the file format is royalty-free; Adobe has published a license allowing anyone to exploit DNG, and has also stated that there are no known intellectual property encumbrances or license requirements for DNG. Adobe stated that if there were a consensus that DNG should be controlled by a standards body, they were open to the idea. Adobe has submitted DNG to ISO for incorporation into their revision of TIFF/EP.
Given the existence of other raw image formats, Adobe's creation of DNG as a competing format implies that DNG is unusual and satisfies objectives that other raw image formats do not. These objectives and the associated characteristics of DNG, as well as assessments of whether these objectives are met, are described below. Increasingly, professional archivists and conservationists, working for respectable organizations, variously suggest or recommend DNG for archival purposes.
These objectives are repeatedly emphasized in Adobe documents:
All of the above objectives are facilitated or enabled by most of these characteristics:
A DNG file always contains data for one main image, plus metadata, and optionally contains at least one JPEG preview. It normally has the extension "dng" or "DNG".
DNG conforms to TIFF/EP and is structured according to TIFF. DNG supports various formats of metadata, (including Exif metadata, XMP metadata, IPTC metadata), and specifies a set of mandated metadata.
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