Supported and Preferred File Formats

Based on current digital data curation best practice and recommendations, the Williams College Archives recommends the following file formats. Please take these recommendations into consideration when determining the file format in which to save records during their active lifecycle. The longer the active lifecycle is anticipated to be, the greater the need to use formats ranked as medium or high confidence.

A short list of preferred and supported formats are listed in order of preference:

Images, Still

  • Preferred: TIFF
  • Supported: JPG, PNG, JPG2000

Images, Moving

  • Preferred: MPEG-4
  • Supported: MPEG-2, MPEG-1, AVI


  • Preferred: WAV
  • Supported: AIFF, MP3, AAC

Text Documents

  • Preferred: PDF/A
  • Supported: Unicode Text, PDF, ACSII

Web Archiving

  • Preferred: WARC

More information

Media Type Preservation Plan

Once records have become inactive and are transferred to the Archives, our primary preservation strategy is to normalize files to preservation and access formats upon ingest. The choice of access formats is based on the ubiquity of viewers for the file format. All preservation formats are open standards.

Additionally, the choice of preservation format is based on community best practices, availability of open-source normalization tools, and an analysis of the significant characteristics of each media type. We also maintain the original format of all ingested files to support future migration and emulation preservation strategies as needed.

Questions? Contact us.