142 · Representative Documents: Format Policies
RUcore. Born Digital Still Images
IBB • RUcore Preservation Standards • Born Digital Still Images Rev: 11/18/2010
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images that were barely acceptable even for computer equipment of the time, much less for print media.
Nonetheless, attempts were made by early adopters to use the technology for permanent preservation,
and the results are that the digital images produced are unacceptable for viewing.
Indeed, for our purposes, digital cameras are only now being produced that can match the
exacting standards that RUcore has laid out for acceptable, preservation-grade images. As the quality
has improved, so has the acceptance and adoption of this hardware for general use photography. This is
an important turning point for RUcore, as although our repository has a number of professional grade
images in our collections, the majority of the photographs we have preserved thus far are often donated
family photographs, amateur stills, and images that were generally produced using consumer equipment.
As a result, we can expect that in the not-too-distant future, we may be expected to preserve amateur as
well as professional digital images that are deemed to capture images and moments that are
In preparation for this, it is essential that RUcore adhere to a standard for which we will accept
born digital images for inclusion in the repository.
Why have a separate standard from those for scanning photographs and documents?
At first glance, it might seem very easy to take the established standards for photograph and
document digitization, and simply apply them as-is to digital photography. Indeed, the two processes
share some similarities, and some of the requirements established for digitization should serve as the
basis for establishing comparative standards for born digital still images. However, there are a few key
differences between digital photography and analog digitization that make a broad application of a
single standard impractical. Consequently, the two workflows need to be viewed from different
paradigms to fully understand them and appreciate their differences.
Perspective is everything: digitization terms redefined
The best way to understand the differences between digital photography and digitization
workflows is to view their intended purposes.
Digitization, or simply scanning, is intended to take an object recorded on an analog medium
such as film, slides or paper. From this, we use an array of equipment and software to create a digital
facsimile, with the intent of making the digital form represent the source object as accurately as possible.
Consequently, the workflow, specifications and terminology are centered around this process.
Digital Photography on the other hand, is a process where the digital form is the primary,
original storage medium. With digital photography, there is no physical medium that can accurately be
described as the “original.” In order for the digital format to take the primary role in recording and
preservation, the hardware must be designed differently, and procedures and terminology have to take
significantly different characteristics from digitization.
These differences in purpose and perspective result in important variations in how images are
acquired and described:
Resolution: PPI vs. Megapixels: The most important difference between digitization and
digital photography is the issue of resolution. Those familiar with digitization have grown accustomed
to expressing resolution in terms of pixels per inch (ppi). This is because for digitization purposes,
resolution is a function that expresses how accurately a scan will replicate the original. the higher the
ppi, it is presumed, the higher the quality of the resulting digital image will be.
Digital photography, however, limits the relevance of ppi in terms of creating the original
photograph. As image sensor sizes can vary greatly from one camera to the next, it is possible for two
different camera models to arbitrarily assign widely different ppi values to their images, yet still produce