Editing Digital Negative (section)

==Technical summary==
A DNG file always contains data for one main image, plus metadata, and optionally contains at least one JPEG preview.<ref name="DNGspecification"/> It normally has the extension "dng" or "DNG".

DNG conforms to [[Tag Image File Format / Electronic Photography|TIFF/EP]] and is structured according to [[Tagged Image File Format|TIFF]]. DNG supports various formats of metadata  (including [[Exchangeable image file format|Exif metadata]], [[Extensible Metadata Platform|XMP metadata]], [[International Press Telecommunications Council|IPTC metadata]]) and specifies a set of mandated metadata.<ref name="DNGspecification4">Adobe: [https://helpx.adobe.com/content/dam/help/en/photoshop/pdf/dng_spec_1_6_0_0.pdf DNG Specification] (Section 4)</ref>

DNG is both a raw image format and a format that supports "non-raw", or partly processed, images.<ref name="DNGspecification"/> The latter (non-raw) format is known as "Linear DNG".<ref>Barry Pearson: [http://www.barrypearson.co.uk/articles/dng/linear.htm Linear DNG]</ref> Linear DNG is still scene-referred<ref name="Scene-referred">CIE: "Scene-referred": [http://eilv.cie.co.at/term/567 image state, scene-referred] {{Webarchive|url=https://web.archive.org/web/20130511215142/http://eilv.cie.co.at/term/567 |date=2013-05-11 }}</ref> and can still benefit from many of the operations typically performed by a raw converter, such as white balance, the application of a camera color profile, HDR compositing, etc. All images that can be supported as raw images can ''also'' be supported as Linear DNG. Images from the [[Foveon X3 sensor]] or similar, hence especially [[Sigma Corporation|Sigma]] cameras, can ''only'' be supported as Linear DNG.

DNG can contain raw image data from sensors with various configurations of [[Color filter array|color filter array (CFA)]]. These include: conventional [[Bayer filter]]s, using three colors and rectangular pixels; four-color CFAs, for example the [[RGBE filter]] used in the [[Sony Cyber-shot DSC-F828]]; rectangular (non-square) pixels, for example as used in the [[Nikon D1#D1H and D1X|Nikon D1X]]; and offset sensors (for example with octagonal pixels) such as [[Super CCD]] sensors of various types, as used in various [[Fujifilm]] cameras. (Or combinations of these if necessary). DNG specifies metadata describing these individual parameters; this is one significant extension to [[Tag Image File Format / Electronic Photography|TIFF/EP]].

When used in a [[CinemaDNG]] movie clip, each frame is encoded using the above DNG image format. The clip's image stream can then be stored in one of two formats: either as video essence using frame-based wrapping in an [[Material Exchange Format|MXF]] file, or as a sequence of DNG files in a specified file directory.

Contrary to its name (Digital Negative) the DNG format doesn't distinguish negative and positive data<ref name="DNGspecification"/> - all data is considered to be describing a positive image. While this is not an issue when working with images from digital cameras (which are always positive), working with scanned (by a [[film scanner]] or [[DSLR]] [[copy stand]]) film negatives saved as raw DNG files is complicated, because the resultant image is not automatically inverted and thus impossible to be used directly. A way to get around this is using an inverted curve in the photo editing application, however this reverses the effect of the image controls ([[Exposure (photography)|Exposure]], Shadow and Highlight details, etc.) which complicates the photo editing.