Friday, January 22, 2010

Digital Preservation and Digital Copies

From now on, I am making it a rule to refer to digital files made of physical objects as digital copies. This is to differentiate them from those files now referred to as born-digital, where there is no physical original. I not only believe this is more accurate, but also when discussing the preservation of these files, it is important to note if you are preserving a copy or an original.
When you are preserving a copy, you are mostly concerned with protecting your financial investment represented in real costs as well as in effort. In terms of digital copies, there are several ways that your investment is at risk. Besides the normal liabilities of nature and god, there is digital corruption and mechanical failure. There is also the concern that the format or method of storing the file may become obsolete. In addition, there is the real concern that the standards, under which the file was created, may become obsolete or the quality of your files no longer meets the needs of the rapidly advancing technology. In other words, you may need to recreate them for a more sophisticated technology. This last risk is one many early adopters have already experienced. Actually, several visual resource professionals have observed this within their own careers, where photographs were replaced by lanternslide, which were replaced by film slides, which are now being replaced by digital copies.
Given that we do want to protect these copies as long as they are viable, what is the best method of protecting these digital copies? Two things are important, back up and documentation. Fortunately, digital copies can be duplicated without loss of quality. A copy can be stored on several types of media in several locations, hopefully one in a remote location. In fact, it is best to store a copy of your digital collection in another entirely different geographic location. That is where documentation comes in. You need to know not only where the copies are stored, but also the method and the technical metadata documenting the standards under which the files were created.

When most people are discussing preserving a born-digital file, it is in terms of an archive. This is an original artifact, which may someday have inherent value in its own right. Is that not so? As an archival object, it should be stored in a safe and protected environment. In the digital realm, this means inspection, migration and redundancy and is very costly. In addition, if the digital artifact is valued in its own right, such as a Web posting of the 2004 election, then you must also preserve the software and hardware required to read the file. Think of Thomas Edison’s cylinders. If your collection contained some, would you not want to hear what they heard then?

However, the question to me is a born-digital file of value because of it format or its content. Clearly, it would be a shame not to be able to hear an Edison cylinder, but are we poorer for not preserving all of them? If you accept that it is the content not the format or media that is to be preserved, you might even progress to questioning what media is the best way to preserve that content. In other words is digital media the best way to preserve content.
When we first began to make digital copies of collections, it was adamantly stated that it was for the purpose of ACCESS not preservation. If we stick with that argument now that we have digital originals, for other then protection of investment, should we preserve the originals in their digital format? Do we preserve something, just because it exists or find the best a format in which to preserve it? We could of course always keep a digital copy for access.