Sustainability of Digital Formats: Planning for Library of Congress Collections

JFIF is a minimal file format that enables JPEG bitstreams to be exchanged between a wide variety of platforms and applications.  It does not include any of the advanced features (like tagged headers) found in the TIFF specification.  JFIF conforms to the interchange format syntax specified in JPEG Standard (ISO/IEC 10918-1, Annex B); its only additional requirement is the mandatory presence of the application segment APP0 marker right after the SOI (Start of Image) marker.

The specification for JFIF 1.02 was originally published in 1992, and made available publicly at http://www.jpeg.org/public/jfif.pdf. In 2011, the International Telecommunication Union (ITU) published essentially the same specification as a recommendation ITU-T T.871 (05/2011). In 2013, the same version of JFIF was approved as ISO standard ISO/IEC 10918-5:2013. See History Notes below, for more detail

JFIF_1_02 has been assigned PRONOM PUID fmt/44. The earlier versions have PRONOM identifiers as follows: JFIF v. 1.00, PUID fmt/42;  JFIF v. 1.01, PUID fmt/43. The PRONOM Web page for JFIF 1.02 (consulted June 16, 2019) states that JFIF was developed prior to there being an official file format as a wrapper for JPEG encoding and thus JFIF "rapidly became a de facto standard." PRONOM also notes that "other types of compression are available through JPEG extensions, including progressive image buildup, arithmetic encoding, variable quantization, selective refinement, image tiling, and lossless compression, but these may not be supported by all JFIF readers and writers."

May be used in initial-state picture creation; often used for middle- and final-state archiving or end-user delivery.

Limited, but some technical metadata is provided by the application segment APP0, and some can be derived in other ways. For detail, see Action Plan Background: JFIF 1.02 (pp. 3-4 - link from Internet Archive) from the Florida Center for Library Automation (FCLA), now known as the Florida Academic Library Services Cooperative.

Accessibility Features

Accessibility for still image content is often supported by the use of alt text when displayed on the web. The carriage of this data is typically not embedded in the file itself but rather in the HTML code. See W3C's Images Tutorial for the Web Accessibility Initiative.

Likely limited accessibility support because embedded metadata does not include image descriptions. Comments welcome.

See JPEG_DCT_BL and JPEG_DCT_EXT.

According to the SPIFF article in the Encyclopedia of Graphics File Formats, "JFIF took a shortcut by attempting to require that all JFIF images have a gamma of 1.0. That requirement has been widely ignored because many pre-existing images have other gamma values, and, as it turns out, a gamma of around 0.4 to 0.5 is technically superior." SPIFF marks its files with the gamma value.

Paraphrased from James D. Murray and William vanRyper's Encyclopedia of Graphics File Formats (O'Reilly and Assoc, 1994, ISBN 1565920589): The JPEG bitstream stores 16-bit word values in big-endian format. JPEG data in general is stored as a stream of blocks, and each block is identified by a marker value. The first two bytes of every JPEG stream are the Start Of Image (SOI) marker values FFh D8h. In a JFIF-compliant file there is a JFIF APP0 (Application) marker, immediately following the SOI, which consists of the marker code values FFh E0h and the characters JFIF in the marker data, as described in the next section. In addition to the JFIF marker segment, there may be one or more optional JFIF extension marker segments, followed by the actual image data.

From http://www.jpeg.org/jpeg/index.html as of March 2012 (link now via Internet Archive): "[T]he file format was created originally by Eric Hamilton, the then governor of JPEG as part of his work at C-Cube Microsystems, and was placed by them into the public domain under the name JFIF (available here in the latest version, 1.02)."

In 2011, the International Telecommunication Union published the recommendation ITU-T T.871 (05/2011), which states, "This Recommendation | International Standard is substantially based on the JFIF version 1.02 specification that was produced in 1992. The JFIF version 1.02 specification was widely and freely circulated, and became widely recognized as a de facto standard. This Recommendation | International Standard was developed primarily to formalize the JFIF version 1.02 specification."

In 2013, JFIF was approved as ISO standard ISO/IEC 10918-5:2013. Information technology -- Digital compression and coding of continuous-tone still images: JPEG File Interchange Format (JFIF). This standard states, "The identical text is published as Rec. ITU-T T.871 (05/2011)."