Illinois Administrative Code › Title 44 - GOVERNMENT CONTRACTS, GRANTMAKING, PROCUREMENT AND PROPERTY MANAGEMENT › Part 4400 - STATE RECORDS COMMISSION › Appendix E - Sustainable File Formats for Electronic Records - A Guide for Government Agencies

Current through Register Vol. 48, No. 28, July 12, 2024
Electronic records are produced and kept in a wide variety of
				file formats, often dictated by the type of software used to create and access
				a record. Accessibility and user convenience are also common factors that
				determine the use of one format over another. When dealing with electronic
				records that have retention requirements past their initial use, however, one
				must also take into consideration the sustainability of the format used.
Sustainability in this context refers to continued
				accessibility over time. For example, will a given electronic record be
				available for users in ten years? What about twenty? Fifty? While no file
				format can guarantee perpetual accessibility, certain formats have distinct
				advantages over others in this regard. These formats are often referred to as
				"sustainable" formats. Sustainable formats often include the below features:
1) Published Documentation and Open Disclosure: Specifications
				for the format are published and accessible to the public. This means that
				anyone who wants to create tools to work with the format can do so with no
				restrictions of copyright. Formats that share these characteristics are
				commonly called "open-source" or "non-proprietary". Because anyone can create
				tools to access such formats they have a low chance of becoming inaccessible in
				the future, even if the formats themselves become obsolete.
2) Widespread Adoption and Use: The more widely a format is
				used, the more likely it is to have multiple tools used to access and
				manipulate it. This reduces the chance of a format becoming inaccessible due to
				one software publisher going out of business. Widespread adoption also serves
				as an indicator of general format stability, and serves as a safeguard against
				loss of accessibility. A wider user base means more stakeholders who have a
				vested interest in keeping a format going.
3) Self-describing Formats: These formats contain metadata
				(data about the data) within their structure that interprets the content,
				context and structure of the file. This means that descriptive information (the
				file name, date of creation, identification of data within the file, for
				example) can be kept within the file itself, and external documentation is not
				required. When discussing long-term preservation this is particularly
				important, since records often become disassociated from their original
				software environment and accompanying files. The more self-contained a format
				is, the better the chances of the data contained within being accessible down
				the road.
4) Unencrypted Files: Electronic records with long-term
				retention should not be encrypted in any way, as this can severely compromise
				the future accessibility of those records. Encryption methods change
				dramatically over time, and the specific software tools needed to access
				current encrypted records may not exist in the future. A good electronic
				records management system can handle security, restricting access to records as
				needed, while leaving the records themselves unchanged.
The following is a list of formats currently recommended for
				long-term preservation by the Illinois State Archives.
Best Choice:
PDF/A (Portable Document Format / Archives): A
				variant of PDF that is specifically aimed at long-term preservation, its
				specifications are published in the standard ISO 19005-1:2005. It sacrifices
				certain functions, such as the ability to have external hyperlinks or embed
				audio or video, for the sake of greater reliability. The most notable different
				between PDF and PDF/A is the latter's ability to embed all necessary fonts
				within the file itself. This makes the file totally self-extracting, without
				any need to access external font information to properly present the formatting
				of the document. PDF/A also embeds descriptive metadata within the file itself,
				making it self-describing. These two factors make PDF/A the preferred format
				for long-term preservation of textual electronic records, both born-digital and
				digitized. Files can be converted to PDF/A by a number of different software
				tools and plug-ins to existing word-processor software.
Other Options:
PDF (Portable Document Format): A format commonly
				used to present formatted, page-oriented documents. PDFs can contain text,
				images, graphics, video and audio, as well as hyperlinks to outside documents.
				Originally created by Adobe Systems as a propriety format, the source code for
				PDF and its variants have since been made freely available, making it an
				open-source format. PDF is widely adopted around the world. Some later versions
				of PDF can include self-describing metadata. PDFs are acceptable for short to
				medium-term storage, but are not suitable for long term (20+ years) or
				permanent preservation. For long-term applications the PDF/A variant is
				preferred.
XML (Extensible Markup Language): A standard format
				for structured documents and data on websites, XML is also a preferred format
				for the preservation of metadata associated with records. XML is maintained and
				developed by the World Wide Web Consortium (W3C), but is open-source. XML
				enjoys nearly universal adoption, and can be accessed and worked on by scores
				of freely available software tools. XML is self-describing, but requires
				association with an appropriate schema (also freely available) in order to
				properly render all formatting.
HTML (Hypertext Markup Language): A standard format
				for structured documents and data on websites currently maintained and
				developed by the World Wide Web Consortium (W3C). HTML is open-source, and is
				universally adopted. Unlike XML, HTML does not contain descriptive metadata
				headings. This limits the machine-readability of HTML, particularly when
				attempting to perform advanced search functions within files.
Plain Text: The most basic form of text file, plain
				text can be rendered by any software that can read text, across any platform.
				Plain Text renders only basic characters, spaces and punctuation, however, and
				does not preserve formatting such as italics or bold letters. It is therefore
				typically used only for relatively small amounts of information such as
				software instructions or short notes. Plain Text is open-source and universally
				adopted. Common file extensions for Plain Text include .txt and .text.
ODF (OpenDocument Format): An XML-based file format
				used for spreadsheets, charts, presentations and word processing documents. ODF
				was developed by Sun Microsystems, but is an open format, is freely available
				to anyone and has been published as an ISO standard (ISO/IEC 26300:2006). Owing
				to its relatively recent creation (2005) ODF is not as widely adopted as some
				other formats, but it is supported by almost all current office suites and word
				processing programs. File extensions for ODF files vary depending upon the
				specific type of file, but include .odt (word processing), .ods (spreadsheets)
				and .odp (presentations).
Still Images
Best Choice:
TIFF (Tagged Image File Format): TIFF was initially
				created in the 1980s in an effort to standardize file formats created by
				commercial scanners. The format has gone through a number of revisions since
				then, becoming an international standard for electronic images. The format is
				currently owned by Adobe Corporation, but the specifications are open and
				freely available. Unlike many image file formats, TIFF is uncompressed. This
				means that the files are larger than a compressed format (such as JPEG) but
				there is no loss of data. This ensures that the file can be reproduced over
				time at its full fidelity. TIFF files can contain "tags" that store descriptive
				metadata about the file. TIFF files may have a file extension of .tif (Windows)
				or .tiff (Macintosh).
Other Options:
JPEG 2000 (Joint Photographic Experts Group):
				JPEG-2000 was created by the Joint Photographic Experts Group in 2000 as a
				next-generation format for electronic images. The format is part of an
				international standard: ISO/IEC 15444:2004. JPEG-2000 files can be compressed
				in either lossy or lossless fashion, although only the lossless variety is
				acceptable for long-term preservation. The format is still relatively new, and
				thus does not have the same wide-spread use as TIFF. This makes it a slightly
				riskier choice for preservation, although usage of the format is growing. The
				lossless compression of JPEG 2000 provides some space savings over TIFF, but it
				may be better suited as a format for access rather than preservation. The
				standard file extension for JPEG 2000 is .jp2.
PNG (Portable Network Graphics): A file format
				initially created with the approval of the World Wide Web Consortium (W3C) as a
				replacement to GIF (Graphics Interchange Format). PNG is most often used to
				present images on the web, and can be accessed with a wide variety of web
				browser and image display software. PNG uses a "lossless" compression algorithm
				which reduces the size of the file without losing any data. This means that
				images in PNG format do not suffer from "generation loss," where the quality of
				an image suffers over time with repeated use. Specifications for PNG are open
				and freely available, and the format can contain extensive metadata within its
				structure.
Spreadsheets
Due to the complexity of spreadsheet structure it is
				challenging to perfectly represent data over time. Different software uses
				varied means to record formulae and link data, and so advanced functions are
				not always replicable in more open formats. The below formats represent the
				best approach for long-term accessibility, but both may be unable to represent
				certain formatting or functions of spreadsheets originally created in formats
				such as Microsoft's XLS. Agencies may want to save copies of spreadsheets with
				long-term retention in both the native format and in one of the below. This
				redundant method can preserve the maximum functionality of the spreadsheet
				while still protecting the core data from format obsolescence.
CSV (Comma Separated Values): A simple format which
				can be used to represent spreadsheet data. CSV files can be accessed with any
				spreadsheet software or text editor, but at the cost of potential loss of
				advanced functionality enjoyed by more proprietary spreadsheet formats. There
				is therefore a tradeoff with using CSV: universal interoperability is excellent
				for long-term preservation, but the loss of advanced formulae may compromise
				the core data of the record. Basic spreadsheets containing tabular data without
				advanced functions may be better served by CSV than others.
ODF: (See previous entry for general data on ODF)
				The spreadsheet format of ODF, .ods, is a good choice for preservation of
				spreadsheets, as it supports more advanced functionality than CSV. However,
				spreadsheets originally created in other formats such as XLS may suffer some
				functionality loss upon conversion to ODF due to the non-standardized methods
				by which different software execute formulae.
Audio
Best Choice:
BWF (Broadcast WAVE Format): A variant of the WAVE
				format, BWF (sometimes called BWAVE) was developed by the European Broadcasting
				Union with long-term preservation in mind. BWF takes the existing WAVE file
				structure and adds additional metadata support. The specifications for BWF are
				open and freely available, and the format is a de facto standard for digital
				audio for those in the radio, motion picture and television industries. It is
				also used extensively by audio archives throughout the world. The format is
				self-describing, as it contains its own structural and descriptive metadata.
				BWF files are uncompressed, and can be played by any software that is WAVE
				compatible. In order to display, add or modify metadata in a BWF file, however,
				one must use software that specifically supports the format. Free software is
				available that can attach BWF metadata to existing WAVE files. The file
				extension for BWF is .wav, the same as standard WAVE files.
Other Option:
WAVE (Waveform Audio File Format): WAVE is a format
				created by Microsoft and IBM in the early 1990s. Though proprietary, the format
				is fully documented and has been used as the basis for the
				preservation-oriented variant BWF (see above entry). WAVE files are
				uncompressed, so they lose no audio data as with some other audio formats. The
				format also enjoys near-universal adoption, as it is compatible with virtually
				every audio player available, across computer platforms. Software utilities to
				convert other formats to WAVE are plentiful and inexpensive (or free). WAVE has
				limited metadata capabilities, so is a second choice for long-term preservation
				behind BWF (see above). WAVE can still be an acceptable format for
				non-permanent audio, provided that appropriate external metadata is associated
				with the WAVE files.
Video
Whereas best practices typically dictate that only
				uncompressed formats be used for preservation of electronic content, the area
				of video preservation becomes more complex. Uncompressed video can take up huge
				amounts of space in a storage environment, and thus formats utilizing
				"lossless" or "near-lossless" compression have become more acceptable in some
				cases. Compression of these types utilizes algorithms to reduce the size of a
				file without irrevocably losing any data. This can be compared to "lossy"
				compression, which sacrifices some data to achieve smaller size. Lossy
				compression is unacceptable for long-term preservation because it permanently
				alters the structure of digital content and can lead to gradual reduction in
				quality over time.
MPEG-4 (Motion Picture Experts Group): MPEG-4 is an
				open-standard format developed by the Motion Picture Experts Group as a format
				for encoding video content for dissemination on the web. There are two main
				encoding versions, and numerous subcategories, of the format. Documentation for
				all varieties of MPEG-4 is extensively published as part of an international
				standard: ISO/IEC 14496-14:2003. The compression of a given MPEG-4 video file
				will depend upon the specific software and coding used in its creation, and can
				range from lossy to lossless. For long-term preservation only lossless or
				near-lossless compression should be used. MPEG-4 supports the embedding of
				descriptive metadata to help support future access. A number of software tools,
				both free and paid for, are available to convert existing video files to MPEG-4
				format.
Motion JPEG 2000 (Joint Photographic Experts Group):
				Motion JPEG-2000 is a derivative of JPEG 2000 which codes and displays video.
				The format is part of an open international standard: ISO/IEC 15444-3:2004.
				Motion JPEG-2000 files can be compressed in either lossy or lossless fashion,
				although only the lossless variety is acceptable for long-term preservation.
				The format is still relatively new, so adoption is not yet as widespread as
				older video formats. A number of software tools are available that can convert
				other video formats into Motion JPEG-2000, and it can support a variety of
				descriptive and structural metadata. File extensions for the format are .mj2
				and .mjp2.