Raw image format

A camera raw image file contains unprocessed or minimally processed data from the of either a digital camera, a motion picture film scanner, or other . Raw files are so named because they are not yet processed, and contain large amounts of potentially redundant data. Normally, the image is processed by a raw converter, in a wide-gamut internal color space where precise adjustments can be made before to a viewable file format such as JPEG or PNG for storage, printing, or further manipulation. There are dozens of raw formats in use by different manufacturers of digital image capture equipment. Raw image files are sometimes incorrectly described as "digital negatives". Rather, the raw datasets are more like exposed but film which can be converted (electronically developed) in a non-destructive manner multiple times in observable, reversible steps to reach a visually desired image. (With exposed film, development is a single event that physically transforms the unexposed film irreversibly.) Like undeveloped photographic film, a raw digital image may have a wider dynamic range or color gamut than the developed film or print. Unlike physical film after development, the Raw file preserves the information captured at the time of exposure. The purpose of raw image formats is to save, with minimum loss of information, data obtained from the sensor. Raw image formats are intended to capture the radiometric characteristics of the scene, that is, physical information about the light intensity and color of the scene, at the best of the camera sensor's performance. Most raw image file formats store information sensed according to the geometry of the sensor's individual photo-receptive elements (sometimes called pixels) rather than points in the expected final image: sensors with hexagonal element displacement, for example, record information for each of their hexagonally-displaced cells, which a decoding software will eventually transform into the rectangular geometry during "digital developing".