EXIF
EXIF stands for Exchangeable Image File Format. It was developed by the Japanese Electronics Industry Development Association (JEIDA) in an effort to simplify and standardize the exchange of data between imaging devices and software. EXIF is a variation of JPEG, used by almost all digital cameras to record extra interchange information to image files as they are taken. The type of information stored in a file varies by camera model, but it can include such things as date and time a photo was taken, resolution, camera settings used for the shot, amount of compression applied, color information, whether or not the flash was fired, shutter speed, and name of the camera owner.
The EXIF specification uses the following existing file formats with the addition of specific metadata tags: JPEG for compressed image files, TIFF for uncompressed image files. It is not supported in JPEG 2000, PNG, or GIF. Version 2.21 was released in September 2003 following the release of DCF 2.0 (CP-3461) digital camera standard.
IPTC
The Information Interchange Model was developed in the 1970's by the International Press Telecommunications Council. It was initially developed as a standard for exchanging information between news organizations and has evolved over time. Around 1994, Adobe Photoshop's "File Info" function enabled users to insert and edit IPTC metadata in digital image files. IPTC allows users to add their own descriptive information within a digital photo or image file. This metadata might include the characteristics of the photo, copyright information, a caption, credits, keywords, creation date and location, source information, or special instructions.
IPTC uses a binary data structure. It can be embedded into JPEG, TIFF, JPEG 2000 or PNG formatted image files. It is not supported in GIF or PCX.
XMP
XMP is an XML-based "Extensible Metadata Platform" developed by Adobe for it's Acrobat PDF format in 2001. Adobe worked with the IPTC to incorporate the old IPTC headers into the new XMP framework and in 2005 the IPTC Core Schema for XMP specification was released. XMP is an open-source, public standard, making it easier for developers to adopt the specification in third-party software. Now maintained by ISO. It uses the Resource Description Framework (RDF) data model and XML as serialization syntax.
XMP can be used in several file formats, such as PDF, JPEG, JPEG 2000, JPEG XR, GIF, PNG, WEBP, HTML, TIFF, Adobe Illustrator, PSD, MP3, MP4, AVI, WAV, RF64, AIFF, PostScript, and EPS.
