There is a "Digital Negative (DNG) Specification Patent License", but it does not actually state that there are any patents held on DNG, and the September 2009 statement was made at least 4 years after this license was published. TIFF/EP began its 5-year revision cycle in 2006. Adobe offered the DNG specification to ISO to be part of ISO's revised TIFF/EP standard. A progress report in October 2008 from ISO about the revision of TIFF/EP stated that the revision "... currently includes two "interoperability-profiles," "IP 1" for processed image data, using ".TIF" extension, and "IP 2" for "raw" image data, ".DNG" extension". It is "IP 2" that is relevant here. A progress report in September 2009 states that "This format will be similar to DNG 1.3, which serves as the starting point for development." DNG has been used by open-source developers. Use by camera makers varies: the largest companies such as Canon, Nikon, Sony, and some others, do not use DNG. Smaller companies and makers of "niche" cameras who might otherwise have difficulty getting support from software companies frequently use DNG as their native raw image format. Pentax uses DNG as an optional alternative to their own raw image format. There are 15 or more such companies, even including a few that specialize in movie cameras. In addition, most Canon point & shoot cameras can support DNG by using CHDK. Canon Raw v2 (CR2) is mostly based on TIFF and lossless Jpeg ITU-T81. Canon Raw v3 (CR3) is based on ISO Base Media File Format (ISO/IEC 14496-12), with custom tags, and unknown "crx" codec. Sony Alpha RAW (ARW) is based on TIFF file format, proprietary Makernote fields and compressions methods. Processing To be viewed or printed, the output from a camera's image sensor has to be processed, that is, converted to a photographic rendering of the scene, and then stored in a standard raster graphics format such as JPEG. This processing, whether done in-camera or later in a raw-file converter, involves a number of operations, typically including: decoding – image data of raw files are typically encoded for compression purpose, but also often for obfuscation purpose (e.g. raw files from Canon or Nikon cameras). demosaicing – interpolating the partial raw data received from the color-filtered image sensor into a matrix of colored pixels. defective pixel removal – replacing data in known bad locations with interpolations from nearby locations white balancing