University of Wisconsin-Madison Libraries Magazine Fall 2016 | Page 18

Capturing Time A Look at Digital Preservation
By Peter Gorman

Some of the oldest items in the Libraries’ collections are documents over 2,000 years old.
They are still readable today because of the durability of the papyrus they’re written on.
The Department of Special Collections also houses a large number of medieval manuscripts
whose vellum pages can easily be read by scholars—provided they understand Latin.
Libraries around the world have been preserving materials like these by keeping them in
climate-controlled facilities away from light, heat, and dust. For many works, however,
careful storage is not sufficient to adequately preserve them. Most 20th-century books are
printed on acidic paper, slowly (or not-so-slowly) disintegrating unless active efforts are
taken to stop the damage or migrate the content to some new medium such as microfilm or,
increasingly, a digital format.
Digitizing for preservation has some real benefits: it may be less expensive than intensive
print conservation methods, perfect copies of the digital files may be made, and access to the
digital files may minimize demand for handling the original materials. However, preserving
digital content itself brings new challenges; one cannot simply put a disk or CD on a shelf
and expect its contents to be preserved. The technical challenges fall into two main areas:
medium and interpretability.
Digital storage costs are continually decreasing, but at the same time, storage media are
continually becoming obsolete. The 5.25” floppy disks and 10Mb PC hard drives of the 1990s
have been replaced by a dizzying array of storage technologies. An institution that needs to
store digital content far into the future must plan for a continual migration of its files to
new storage media, lest it be caught with all of its assets on the digital equivalent of 8-track
tapes. This content must also be constantly monitored against “bit rot,” the gradual decay of
individual bits on a disk that might irretrievably corrupt a file. Preservation systems typically
store al l content on multiple platforms, periodically checking the copies against one another
to ensure their integrity.
Even the best storage program will not preserve digital content if the files have been
created in proprietary formats by obsolete software. Files from some early word processing

Starkey, George 1627-1665 / Secrets reveal’d : or, an open entrance to the shut-palace of the King: containing the greatest treasure in chymistry never yet so
plainly discovered (1669). (Digital Collections).

18 | LIBRARIES Fall 2016

Steve Dast, Digital Collections, scans materials.

and spreadsheet software can no longer be opened and read, even if they’re in perfect digital
condition. Although conversion software exists for many consumer-market formats, libraries
and archives must continually audit their holdings to discover at-risk formats and, if possible,
migrate content to newer, more standard formats.
The Libraries are trying to meet these challenges by relying on international standards
for capturing, encoding, storing, and migrating digital content. However, because the digital
landscape changes so quickly, we need to constantly monitor our content if we want to prevent
the digital decay of millions of dollars’ worth of our cultural heritage. These systems come
at a cost, however, at a time when base budgets are shrinking. Libraries and other heritage
institutions are working together to find creative ways to fund and sustain critical preservation
programs: developing efficient work flows, creating preservation endowment funds, and joining
collaborative initiatives such as HathiTrust and the Digital Preservation Network. It will take
a combination of these methods to ensure that our cultural heritage is preserved for future
generations.

University of Wisconsin–Madison | 19