Significant Properties (SP)

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This section is extracted from the deliverable D4.1 Initial version of environment information extraction tools [Corubolo, F. et al (2014)], p. 17-18

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Maintaining Authenticity

The concept of significant properties (SP) has been much discussed in Digital Preservation (DP) over the past decade (see for example [Lynch, C.. (1999), Hedstrom, M. (2002), PREMIS (2008)], in particular in the context of maintaining authenticity under format migrations, given that some characteristics are bound to change as formats are migrated. The issue here was to identify which properties of an object are significant for maintaining its authenticity.

Significance

Early work in this direction may be found in [Lynch, C. (1999)], where SP are introduced as a “canonical form for a class of digital objects that, to some extent, captures the essential characteristics of that type of object in a highly determined fashion”. Later work [Hedstrom, M (2002)] investigated ways of classifying the properties: “Significant Properties, also referred to as “significant characteristics” or “essence”, are essential attributes of a digital object which affect its appearance, behaviour, quality and usability. They can be grouped into categories such as content, context, appearance (e.g. layout, colour), behaviour (e.g. interaction, functionality) and structure (e.g. pagination, sections).” The concept has been adopted by standards such as [PREMIS (2008)], which describes SP as “Characteristics of a particular object subjectively determined to be important to maintain through preservation actions.” Such characteristics may be specific to an individual digital object (DO), but can also be associated with categories of DO.

An important aspect of SP is that significance is not absolute; a property is significant only relative to (e.g.) an intended purpose [Knight, G. (2008)], or a stakeholder [Dappert, A. (2009)], or some other way of identifying a viewpoint. This intuition is highly relevant to what we describe in the section “Filling the gap”, where significance is considered a key property for collecting relevant information from the environment.

While the concept of SP is useful for digital preservation, in its application it has usually been restricted to internal properties of a DO, for example the size and colour space of an image, or the formatting of text documents, rather than the potentially valuable information that is external to the object itself. There have been some indications of a broader conception: [Hedstrom, M. (2002)] identifies context as a category of SP, [Knight, G. (2010)] refers to the need to preserve properties of the environment in which a DO is rendered, and [Dappert, A.(2009)] introduces the notion of characteristics of the environment. The latter associates environments with functions or purposes; this differs from what we are aiming at, which is to describe the significance of information from a DO’s environment in relation to the purpose the user is following (such as editing the object, processing the object, etc.). We thus see the purpose as qualifying the significance, not the environment – a piece of information is significant for a specific purpose, but not for some other purpose (within the same environment).

Software-based art as example

Within PERICLES, we often draw on Software Based Artworks (SBA) as example (provided by TATE as our case study partner), because they qualify to demonstrate that SPs cannot always be preserved just by preserving their intrinsic metadata. [Lurk, T. (2008)] described that the environment has a special role for born digital media art, as “The digital environment contains both: the core elements of the artistic software as well as the operating system and modules required by the artistic software.”

In [Laurenson, P. (2014)] the important question “What are the Spatial or Environmental Parameters of a Work?” is asked to identify one of the areas of focus for SPs of SBAs. Also, [Falcão, P. (2010)] outlines the “significance of the hardware/software systems for video and software based artworks”. One of her case studies concerning the artwork Becoming by Michael Craig-Martin is a good example to illustrate the dependency of SBAs’ significant properties on the environment: “The randomness was created using Lingo, the programming language for Director. This randomness makes use of the computer’s system clock, and the speed at which images become visible or invisible is also dependent on the speed of the computer.”