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 |
|---|---|---|
| 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)
