Preservation Policy

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Mountain Scholar is committed to providing long-term access to the digital works it contains. Adhering to best practices, Mountain Scholar and CSU Libraries staff use digital preservation strategies that adapt to the changing technological environment.

Preservation steps may include format migration, normalization, and/or emulation. Which steps CSU Libraries staff will take to perpetuate accessibility of a file are determined by the nature of the file format. For example:

  • PDF, TIFF, JPEG, CSV and WAV: More extensive actions will be taken to preserve accessibility for objects in file formats that are fully disclosed, well documented, and widely adopted.
  • Microsoft files, Photoshop, and most video formats: Fewer actions will be taken to preserve usability for file formats that are proprietary and/or undocumented, and those that are considered working formats (e.g., Photoshop, .psd) and/or are not widely adopted.

To assist depositors with selecting file formats that are best suited for preservation, the following tables details support levels for commonly used file formats.

Digital Preservation Support Levels

Support Element Full Support Limited Support
Assigns a persistent identifier that will always point to the object and/or its metadata. X X
Creates provenance records and other preservation metadata to support accessibility and management over time. X X
Provides secure storage and backup. X X
Performs periodic refreshment to new storage media. X X
Performs routine fixity checks using proven checksum methods. X X
Undertakes strategic monitoring of file formats. X
Plans and performs migration to succeeding format upon obsolescence. X

File Support and Preservation Best Practices

The following tables detail the Mountain Scholar preservation support levels for commonly used file formats. Preservation best practices are also described.

Text and Microsoft Office File Formats

Best Practice Guidelines:

  • PDF/A is the preferred version of PDF for archival preservation.
  • Consider converting Microsoft formats with “Limited” support to PDF, PDF/A or CSV for full support.
  • Submissions of HTML files must also include all other referenced files such as CSS files.
  • .txt files should be saved in the UTF-8 (Unicode) character set.
  • Full support of XML and SGML files requires the depositor to include the DTD along with the well-formed XML or SGML file.
Format Extension Support Level
PDF .pdf Full
HTML .html, .htm Limited
Microsoft Word .doc, .docx Limited
Microsoft PowerPoint .ppt, .pptx Limited
Microsoft Excel .xls, .xlsx Limited
CSV .csv Full
Rich Text .rtf Limited
Plain Text .txt Full
SGML .sgm, .sgml Full
XML .xml Full

Image File Formats

Best Practice Guidelines: For long-term preservation, images saved without compression are best. If compression status is not known, preserve the highest quality version (usually the version with the largest file size).

Format Extension Support Level
BMP .bmp Limited
GIF .gif Limited
JPEG .jpg Full
JPEG 2000 .jp2 Limited
PNG .png Limited
Photoshop .psd Limited
TIFF .tif Full

Audio File Formats

Best Practice Guidelines: For long-term preservation, save audio files in non-proprietary formats. Wave files (.wav) are currently the recommended standard.

Format Extension Support Level
MPEG audio .mp3 Limited
Real Audio .ra, .rm, .ram Limited
Wave .wav Full
Windows Media Audio .wma Limited

Video File Formats

There are currently no well-defined standards for preserving video files, except to use the uncompressed version, retaining the original resolution and frame rate (e.g. 1080p24; 720p60, etc.). Mountain Scholar will closely monitor developments in this area and update policies accordingly. In general avoid proprietary and compressed file formats.

Format Extension Support Level
AVI .avi Limited
MPEG-1 . .mp1 Limited
MPEG-2 .mp2 Limited
MPEG-4 .mp4 Limited
QuickTime .mov Limited
Windows Media Video .wmv Limited

Data File Formats

Best Practice Guidelines:

  • For long-term preservation, files should be saved in formats that are:
    • Non-proprietary
    • Unencrypted
    • Uncompressed
    • In common usage by the research community
    • Adherent to an open, documented standard
    • Using standard character encodings (ASCII, UTF-8)
    • The preferred format for tabular data is CSV.
  • Proprietary formats may be included in addition to recommended formats to enhance reusability, but we offer a limited support level for these formats.
  • Accompanying documentation, such README files, should be in plain text or PDF/A.
  • For a more complete list of file formats and characteristics related to their sustainability, see the Library of Congress format descriptions for Dataset Formats and Geospatial Data.
Format Extension Support Level
Microsoft Excel .xls, .xlsx Limited
CSV .csv Full

(Revised September 2019)



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For more information, contact:

Helen Baer
Digital Projects Librarian 
(970) 491-5934

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