File Formats & Guidelines
This web page contains format considerations and recommendations for creating digital content suited for long-term preservation and use. This information was compiled for users of the DRS but could be applied more generally to any digital content intended for long-term preservation. This information will be re-evaluated and updated over time.
Recommended File Formats for Deposit into the DRS
Recommended File Formats for Deposit into the DRS
General Format Considerations
Unfortunately it's not possible to provide a single list of file formats that are appropriate for all use cases. The best formats to use for each of a DRS object's files will vary depending on how those files will be accessed and used, how they were captured or created, and their relationship to other files in the object. When requested, OIS staff will provide guidance on the digital file formats to use for a project if the content will be deposited into the DRS. The factors that are taken into consideration are documented in General Considerations for Choosing File Formats [pdf].
Still Image Formats for Preservation Copies
The formats recommended here are based on preservation considerations only. Other factors such as savings in storage space, that may cause one to choose a particular format, are not considered here. Only the still image formats fully supported by the DRS are listed here.
Acceptable file formats listed in order of preference:
| Preference | Formats |
|---|---|
| 1 | - TIFF uncompressed in any color space supported by TIFF TIFF 6.0 has been commonly used at Harvard for digital master images, and is considered an archival file format suitable for long-term preservation. For more information about the TIFF format see Adobe's TIFF resources. |
| 2 | - JPEG 2000 JP2 profile with lossless compression Some projects depositing content into the DRS have chosen to use JPEG 2000 for digital master images instead of TIFF. JPEG 2000 can offer storage savings - file sizes tend to be smaller and there is an opportunity to use the same file as the preservation and use copy. While JPEG 2000 is becoming more acceptable in the library community as a preservation format, there are still advantages to TIFF over JPEG 2000 for preservation. TIFF uncompressed is a simpler format internally and has more general tool support. For more information about JPEG 2000 see the JPEG 2000 website. |
| 3 | - TIFF with CCITT T.6 (Group 4) compression |
| 4 | - JPEG 2000 JP2 profile with lossy compression |
| 5 | - JPEG/JFIF - TIFF with associated alpha component - TIFF with PackBits (lossless), LZW (lossless), Modified Huffman, or Group 3 Fax compression |
| 6 | - GIF |
Less desirable file formats:
| File format | Suggested alternatives |
|---|---|
| JPEG (non-JFIF) | - TIFF uncompressed - JPEG 2000 JP2 profile with lossless compression |
| TIFF with JPEG (lossy) compression | - TIFF uncompressed - JPEG 2000 JP2 profile with lossless compression |
| PhotoCD | - TIFF uncompressed - JPEG 2000 JP2 profile with lossless compression |
Formats for Use Copies
If your content will be delivered by the DRS delivery services, choose formats for your use files that are compatible with these services.
| DRS Delivery Service | Supported File Formats |
|---|---|
| Page Delivery Service (PDS) | Page images: JPEG2000 JP2, JPEG, GIF, TIFF (bitonal, CCITT Group 4 Fax compression) Page text: Plain text in ASCII or UTF-8 character encoding |
| Image Delivery Service (IDS) | JPEG, GIF, JPEG2000 JP2, TIFF |
| Streaming Delivery Service (SDS) | RealAudio, SMIL with sequential links to RealAudio files |
| Full-text Search Service (FTS) | Plain text in ASCII or UTF-8 character encoding |
| File Delivery Service (FDS) | Technically any format. Initially FDS will only deliver the following formats until additional access/use policy and metadata is developed and implemented: ICC, PDF, Plain Text, SGML, XML, ZIP. |
File Creation Guidelines
File and Directory Names
- OIS Recommendations for File and Directory Names for Long-term Preservation and Access (August 2009) [pdf]
Reformatting and Digitization Guidelines
- Federal Agencies Digitization Guidelines Initiative
Provides guidelines for still images and audio/visual material. - Benchmark for Faithful Digital Reproductions of Monographs and Serials
Developed by the Digital Library Federation, the benchmark is used to set minimum quality levels for the conversion of printed texts.
Portable Document Format (PDF)
- OIS Recommendations for PDF Files Created for Long-term Preservation and Access (October 2009) [pdf]
Format Assessments
JPEG 2000 JP2
- Library and Archives Canada: Environmental Scan of JPEG 2000 Usage in Memory Institutions
Preserving Your Own Files
A few institutions and projects have put together guidelines you can use to preserve your own digital content:
- Digital Private Papers Workbook, Paradigm project (University Libraries of Oxford and Manchester, UK)
Highlighted sections: 'Backup your files', 'Look after your hardware and media', and 'Administer your system' on the Practical Tips page. A summary of the Practical Tips page is found on the Eleven top tips for preserving your personal data page. - Preserving Your Digital Memories web page and printable brochure (Library of Congress)