Digital Negative (DNG) is a patented, open, lossless raw image format developed by Adobe and used for digital photography. Adobe's license allows use without cost on the condition that the licensee prominently displays text saying it is licensed from Adobe in source and documentation, and that the license may be revoked if the licensee brings any patent action against Adobe or its affiliates related to the reading or writing of files that comply with the DNG Specification. 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. Rationale for DNG Adobe states that, given the existence of a wide variety of camera-brand-specific raw image formats, it introduced DNG as a standardized and backward-compatible universal file format. It is based on the TIFF 6.0 standard. Various professional archivists and conservationists, working in institutional settings have adopted DNG for archival purposes. Objectives These objectives are repeatedly emphasized in Adobe documents: Digital image preservation (sometimes known as "archiving"): to be suitable for the purpose of preserving digital images as an authentic resource for future generations. Assessment: The US Library of Congress states that DNG is a recommended alternative to other raw image formats: "Less desirable file formats: RAW; Suggested alternatives: TIFF_UNC, JP2_J2K_C_LL, DNG". The Digital Photography Best Practices and Workflow (dpBestflow) project, funded by the United States Library of Congress and run by the American Society of Media Photographers (ASMP), singles out DNG, and states "DNG files have proven to be significantly more useful than the proprietary raw files in our workflow". Easy and/or comprehensive exploitation by software developers: to enable software to be developed without the need for reverse engineering; and to avoid the need for frequent software upgrades and re-releases to