File Format Recommendations

These recommendations are designed to serve as a general guideline for file formats within the Archives and Special Collections. The Archives will accept all file formats; however, some formats are more sustainable and easier to preserve long term. The Archives ranks formats based on how comfortable we are with maintaining each format. These rankings are High, Moderate and Low.

High Preference indicates that the formats have the most support and the highest probability of long-term stability. The formats are typically openly documented and are not compressed (or have lossless data compression).

Moderate Preference formats do not meet the minimum requirements for long-term retention but come close and for practical reasons, may be necessary for long-term care. These formats are more likely to require migration in order to remain renderable.

Low Preference formats are not recommended or supported for long-term preservation. These files may be difficult to render or provide access to in the future.

Word Processing

  • High preference: PDF/A-1a (.pdf), OpenDocument Text (.odt)
  • Moderate preference: PDF/B-1b (.pdf), Microsoft Word (.doc), Microsoft Open XML (.docx), Rich Text Format (.rtf)
  • Low preference: Corel WordPerfect (.wpd), Lotus WordPro (.lwp), PDF (.pdf)

Plain Text

  • High preference: Plain Text (.txt), Comma-separated file (.csv), Tab-delimited file (.txt)

Structural markup text documents

  • High preference: SGML with DTD/Schema, XML (.xml) with DTD/Schema
  • Low preference: SGML without DTD/Schema, XML without DTD/Schema


  • High preference: OpenDocument Spreadsheet (.ods), Comma-separated file (.csv), Tab-delimited file (.txt), PDF/A-1a (.pdf)
  • Moderate preference: Microsoft Excel (.xls), Microsoft Excel Open XML (.xlsx)


  • High preference: WAVE Format (.wav)
  • Moderate preference: AIFF (uncompressed) (.aif, .aiff), Standard MIDI (.mid, .midi), Windows Media Audio (.wma), MPEG3 (.mp3), MP2 AAC (.m4a)
  • Low preference: Audio CD, DVD-Audio, QuickTime MP4 AAC Protected (.m4p, .m4b), QuickTime MP3, iTunes (.mp3), RealAudio (.rm, .ra), Shorten (.shn), RIFF-RMID (.rmi), Extended MIDI (.xmi), Module Music Formats, Mods (.mod)


  • High preference: Archival format not currently established.
  • Moderate preference: AVI (.avi) MPEG-1 (.mp1), MPEG-2 (.mp3), MPEG-4 (.mp4), Quicktime (.mov)
  • Low preference: Windows Media Video (.wmv)


  • High preference: TIFF (.tif, .tiff), JPG 2000 (.jp2)
  • Moderate preference: JPEG (.jpg, .jpeg), PNG (.png), PDF/A-1a (.pdf), GIF (.gif)
  • Low preference: RAW (.raw, various), Adobe Photoshop (.psd), Kodak PhotoCD, Encapsulated PostScript (.eps), FlashPix (.fpx), PDF (.pdf)