The ABCs of Digital Preservation

April 27 through May 1 of this year marked the American Library Association's 5th Annual Preservation Week. To celebrate, I gave a talk for library staff titled The ABC's of Digital Preservation. The purpose of the talk was to introduce some basic digital preservation concepts, such as choosing file formats, file naming best practices, and the basics of preservation metadata. I also discussed some tools and models for managing digital materials, and tried to demystify some of the acronyms I throw around casually in meetings ("If we follow OAIS, the SIP could contain a TIF and some PREMIS and or METS, and of course the AIP will need an md5...").  You can view the slides of the talk here. 

The talk was well attended, and I got a lot of good feedback and follow-up questions. In this blog post, I'd like to address these questions, and talk about some resources to learn more about topics discussed in my presentation.

First, I'll start with some general resources...

In creating and organizing my presentation, I was inspired by the North Carolina Department of Cultural Resource's Digital Preservation Best Practices and Guidelines. It's a great resource and an excellent starting point.

Read through the archives and follow The Signal, the digital preservation blog of the Library of Congress. They highlight a lot of amazing projects covering all aspects of digital preservation.

Also, the North East Document Conservation Center has some great resources.

Now, on to your questions...

1. Is there a list of file formats defining their function that I could reference?

Yes! The Library of Congress developed this great resource for file format descriptions. The South Carolina Department of Archives and History also has a nice resource on File Formats.

2. Could you point me toward a bibliography of good guides for organizing photographs (or perhaps a workshop)?

Library of Congress's Personal Digital Archiving project has a good, succinct guide to archiving digital photos. Here's another great resource created by MLIS students at Catholic University of America for Preservation Week. Mike Ashenfelder also wrote a great blog post on The Signal answering questions about digital photo archiving (you should check out the webinar he references as well!) And finally, here is an amazing resource for digging into embedding metadata in digital images.

3. Can you tell me more about the Digital POWRR Tool Grid?

"The POWRR Tool Grid v2 provides a set of interactive views designed to help practitioners identify and select tools that they need to solve digital preservation challenges. This Grid is based on the Tool Grid first developed by the Digital POWRR Project, and combines the form and function of the original POWRR grid with the far greater coverage of tools provided by the COPTR data feed."

4. What are the current archival standard for image scans- resolution and bit depth?

The Federal Agencies Digitization Guidelines Initiative (FADGI!) has an excellent document that goes into great detail providing best practices for image scans:  Technical Guidelines for Digitizing Cultural Heritage Materials .  ALTCS, a division of ALA, has also published a helpful guide for Minimum Digitization Capture Recommendations for many types of media.

5. What are the best practices for preserving video files (ideal formats, codecs, etc.)?

Choosing a file format and codec for video preservation master files is complex. A lot depends on available resources, technological expertise, and the context in which files are created and managed. FADGI has done an excellent analysis of the issues involved in their report Digital File Formats for Digital Tape Reformatting. For best practice guidelines for creation and management of digital video, I really love the Activist's Guide to Archiving Video.

6. Bagit …. wait, what?
Check out this video from the Library of Congress. Another place to learn more is Bagit's wikipedia page. And if your ready to use BagIt, you can download it on Github.

7. What to do if a preservation copy has changed? Can you fix it?
Hopefully, you'll have multiple copies of a file, and the preservation copy can be replaced with a "good" one. For situations where this isn't the case, someone with expertise in the file format should be able to address the issue, as explained by @dericed:

8. What are some best practices or tools for data preservation?

A good place to start would be the How-to Guides and Checklists from the Digital Curation Centre. Then read through the rest of their website -- its a gold-mine of information on curating digital research! Library of Congress has recommended formats for datasets and databases, as well as a report on evaluating file formats for datasets and information on types of dataset file formats. Stanford also has a good guide covering many aspects of digital curation for research data. SCAPE is a project of the Open Preservation Foundation that develops software tools and training materials for large scale data preservation.

Written by Jenny Mullins