How Long will Digital Photography Last?
The long-term preservation of traditional photographic medium (AKA Cow Hooves) has a tradition backed by research and known “Best Practices”. Given dark storage and reduced temperature environments, silver based photographic materials can be preserved for hundreds of years. Given a sub-zero environment the time is estimated to be thousands of years. But, what about digital photography?
Digital photography is incredibly fragile and subject to corruption or erasure. It must be stored in redundant media and in redundant locations to be assured that images stored in digital form will still be available in the future. But even if you backup, archive and store your digital images properly, will that guarantee that digital photography will be available in 5, 50 or 500 years from now? Will those steps ensure that photography will be readable and usable forever?
No. . .
The preservation of digital photography and digital content has become a major challenge for society. Since digital forms of media are rapidly becoming the principal forms used to create, distribute and store all manner of content, digital content now embodies much of the nation’s intellectual, social and cultural history. Digital content, particularly photography, is at serious risk of becoming unavailable to our future. If society loses it’s current intellectual, social and cultural history, it’s a major loss for future generations. Imagine if we no longer had access to the Civil War photographs by Mathew Brady, the portraits of people such as Winston Churchill, Babe Ruth or Albert Einstein or the photographic records of the Wright Brothers’ first flight.
In December 2000, Congress appropriated $100 million (rescinded to $99.8 million) for a national digital-strategy effort, to be led by the Library of Congress. The Library of Congress led the formation of a collaborative project called the National Digital Information Infrastructure and Preservation Program (NDIIPP). The project furthers the Library’s mission “to make its resources available and useful to Congress and the American people and to sustain and preserve a universal collection of knowledge and creativity for future generations.”
One of the most critical factors regarding the long-term preservation of digital content is the format in which the digital “objects” are stored. In order to have “sustainability” you need the ability to maintain a digital object in a technological environment in which users and archiving institutions operate. Sustainability is significant whatever strategy may be adopted as the basis for future preservation actions: migration to new formats, emulation of current software on future computers, or a hybrid approach.
NDIIPP has identified seven sustainability factors that apply across digital formats for all categories of information. These factors are:
Disclosure refers to the degree to which complete specifications and tools for validating technical integrity exist and are accessible to those creating and sustaining digital content. 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.
Adoption refers to the degree to which the format is already used by the primary creators, disseminators, or users of information resources. This includes use as a master format, for delivery to end users, and as a means of interchange between systems. If a format is widely adopted, it is less likely to become obsolete rapidly, and tools for migration and emulation are more likely to emerge from the industry without specific investment by archival institutions.
Transparency refers to the degree to which the digital representation is open to direct analysis with basic tools. Digital formats in which the underlying information is represented simply and directly will be easier to migrate to new formats and more susceptible to digital archaeology. Transparency is enhanced if textual content-including metadata embedded in files is encoded in standard character encodings and stored in natural reading order. Many digital formats used for disseminating content employ encryption or compression. Encryption is incompatible with transparency; compression inhibits transparency.
Digital objects that are self-documenting are likely to be easier to sustain over the long term and less vulnerable to catastrophe than data objects that are stored separately from all the metadata needed to render the data as usable information or understand its context. A digital object that contains basic descriptive metadata and incorporates technical and administrative metadata relating to its creation and early stages of its life cycle will be easier to manage and monitor for integrity and usability and to transfer reliably from one archival system to its successor system.
External dependencies refers to the degree to which a particular format depends on particular hardware, operating system, or software for rendering or use and the predicted complexity of dealing with those dependencies in future technical environments.
Impact of patents
Patents related to a digital format may inhibit the ability of archival institutions to sustain content in that format. Although the costs for licenses to decode current formats are often low or nil, the existence of patents may slow the development of open source encoders and decoders and prices for commercial software for transcoding content in obsolescent formats may incorporate high license fees.
Technical protection mechanisms
To preserve digital content and provide service to users and designated communities decades hence, custodians must be able to replicate the content on new media, migrate and normalize it in the face of changing technology, and disseminate it to users. Content for which a trusted repository takes long-term responsibility must not be protected by technical mechanisms such as encryption, implemented in ways that prevent custodians from taking appropriate steps to preserve the digital content and make it accessible to future generations.
As can be seen from the above seven sustainability factors, digital photography is at serious risk. Why? Undocumented, proprietary raw file formats. While some may argue that there are file formats available that do mitigate the risks, those file formats, such as JPG or TIFF, do not provide a format for the storage of the unprocessed raw sensor data. But it is the original raw sensor data that we need to preserve because as we’ve seen in just a few short years, the software for processing the raw data has improved considerably. With digital photography, we have the unprecedented situation that original raw captures will actually improve over time because the software and algorithms to decode and access the raw data will improve over time.
However, the sustainability of raw file formats is at serious risk. Currently, there are over 100 raw file formats from over 15 different camera companies. With each new camera that is released we, in effect, add yet another new raw file format. The undocumented status and the proprietary nature in which these file formats are produced violate the tenets outlined by the NDIIPP.
How did this situation come to pass? In the history of photography, it has been the traditional role of film manufacturers to develop standards relating to the preservation of photographic materials. The camera companies have had no such responsibility and have developed no such standards. Camera companies have no facilities for testing nor any background or experience in long term preservation-it’s simply an issue in which they have no experience or skills. When the digital photography revolution began, the camera companies found themselves in the unusual and rather awkward situation of expanding their traditional role of producing cameras and lenses into a role of processing the digital capture. Based loosely upon existing TIFF standards, in particular, TIFF-EP standards, camera companies created short term solutions to deal with technical issues of writing raw sensor data to disk or storage. Each sensor type and its raw file format was designed for the purpose of solving the short term problem of writing the data. Little or no thought was given to working towards standards that would help ensure long term access to the data. Already, there are cameras and raw file formats that are unsupported by the companies that created them…
The photographic industry is in the middle of a revolution – digital.
But, digital technology has the nasty habit of creating new challenges and significant problems where none existed before adoption of the technology. The development of digital cameras is that kind of challenge and problem now facing the photographic industry. The camera companies, so far, are failing to address the long term preservation of digital photography by their persistent use of undocumented and proprietary raw file formats. This must change. Standards must be developed and adopted that ensure sustainability of digital photography. This is the camera companies’ new responsibility and if they do not adopt it willingly, they must be forced to adopt it by the photographic industry.