Sustainability: Disclosure
Degree to which complete specifications and tools for
validating technical integrity exist and are accessible to those
creating and sustaining digital content. A spectrum of
disclosure levels can be observed for digital formats.  What is
most significant is not approval by a recognized standards
body, but the existence of complete documentation.
Preservation of content in a given digital format over the long
term is not feasible without an understanding of how the
information is represented (encoded) as bits and bytes in
digital files.
Examples:
TIFF image format well documented, many products and shareware
MrSID image format partially documented, proprietary elements
protected