Preferred File Formats

The level of support given depends on a confidence level associated with a file format (high, medium, low) and the tools available to address specific preservation issues.  Current confidence levels by generic file types are provided below.  File formats are listed in alphabetical order under the confidence level.

Text

Highest confidence:

  • PDF/A-1 - ISO 19005-1 (.pdf)
  • Plain Text - with encoding: US-ASCII, UTF-8 (.txt)
  • XML - with included schema (.xml)

Medium confidence:

  • HTML -  include a DOCTYPE declaration (.htm, .html)
  • LaTeX with referenced files (.latex, .tex, .ltx)
  • Microsoft Word 2007 or newer (.docx)
  • PDF - with embedded fonts (.pdf)
  • Rich Text Format 1.x (.rtf)
  • SGML (.sgml)

Lowest confidence:

  • Microsoft Word 2003 or older (.doc)
  • PDF - encrypted (.pdf)
  • WordPerfect (.wpd)

Raster Images/Graphics

Highest confidence

  • PNG - 24bit (.png)
  • Tiff - uncompressed (.tif, .tiff)

Medium confidence

  • Digital Negative DNG (.dng)
  • GIF (.gif)
  • JPEG2000 - lossless (.jp2)
  • JPEG/JFIF (.jpg)
  • PNG -  8 bit (.png)
  • Tiff - compressed (.tif, .tiff)

Lowest confidence

  • JPEG2000 - lossy (*.jp2)
  • Photoshop document (.psd)
  • RAW formats (.raw, etc)

Vector Graphics

Highest confidence

  • SVG -- no JavaScript binding (.svg)

Medium confidence

  • Computer graphics Metafile (.cgm)

Lowest confidence

  • Encapsulated Postscript (.eps)

Spreadsheet / Database

Highest confidence

  • Comma- or tab-separated Values (.csv, .tsv, .txt)
  • Delimited text (.txt, .csv)
  • SIARD: Software Independent Archiving of Relational Databases (.siard)

Medium confidence

  • Excel 2007 or newer (.xlsx)
  • Open Document Spreadsheet (.ods)
  • XML (.xml)

Lowest confidence

  • Excel 2003 or older (*.xls)

Audio


Highest confidence

  • AIFF - uncompressed (.aif, .aiff)
  • Free Lossless Audio Codec (.flac)
  • WAV - uncompressed (.wav)

Medium confidence

  • Advanced Audio Coding (.mp4)
  • Apple Lossless Audio Codec (ALAC) (.m4a)
  • MP3  (*.mp3)
  • SUN audio -- uncompressed (.au, .snd)

Lowest confidence

  • AIFC -- compressed AIFF (.aifc)
  • RealAudio (.ra, .rm)
  • WAV -- compressed (.wav)
  • Windows Media Audio (.wma)

Video

Highest confidence

  • AVI - uncompressed (.avi)
  • QuickTime - uncompressed, motion JPEG (.mov)

Medium confidence

  • Material Exchange Format - uncompressed (.mxf)
  • Motion Jpeg2000 (.jp2)
  • Mpeg-1, mpeg-2 (.mp1, .mp2)
  • MPEG-4 - preferably H.264 (.mp4)

Lowest confidence

  • RealVideo (.rv, .rm)
  • Quicktime - compressed (.mov)
  • Windows Media Video (.wmv)

PowerPoint or similar

Highest confidence

  • [none provided]

Medium confidence

  • OpenOffice (.odp)
  • Powerpoint 2007 or newer (.pptx)
  • Portable Document Format (.pdf)

Lowest confidence

  • PowerPoint 2003 and older (.ppt) (2003 and older)

Websites

Highest confidence

  • WebARChive (.warc)

Medium confidence

  • Internet Archive ARC (.arc)

Lowest confidence

  • Files from content management system

Email

Highest confidence

  • MBOX (.mbox)
  • Exports as plain text with message header and context (.txt)

Medium confidence

  • EML (.eml)
  • MSG (.msg)
  • PST (.pst)

Lowest confidence

  • [none provided]

Geospatial

Highest confidence

  • geoJSON (.json, .tif)
  • Geotiff (.tif)

Medium confidence

  • ESRI Database file
  • ESRI shape file
  • GeoMarkup (GML)
  • GeoPackage
  • Keyhole markup (KML)

Lowest confidence

  • Other geospatial files

CAD (Computer Aided Design)

Highest confidence

  • PDF/E - ISO 24517-1:2008 (.pdf)

Medium confidence

  • AutoCad (.dwg)
  • AutoDesk’s Drawing Interchange File Format/Data eXchange Format (.dxf)

Lowest confidence

  • [none provided]