File formats for long-term preservation.
Are you aware of how important it is to choose a suitable file format to ensure future access to digital archives and records?
In this article, I will provide a brief introduction to the topic and present file formats suitable for long-term preservation.
Introduction
A consequence of rapid technological development is that everything within IT becomes obsolete quickly. Programs and platforms are constantly updated and expanded, new ones emerge, and others are discontinued. The same applies to file formats. If you try to open a Microsoft Word DOC file from the 1990s, it may look strange and be improperly formatted. Perhaps you have files from now discontinued and unsupported programs that used undocumented file formats, which are only compatible with the respective programs where they were created or require hardware that has long since been discontinued.
Over time, there may therefore be a risk that digital archives and records can no longer be opened, displayed correctly, or lose metadata – all scenarios that can be costly to resolve and have legal and business consequences.
One way to guard against the above problem is to use relevant file formats that are suitable for long-term preservation and take retention periods and expected future use into account.
File Formats for Long-term Preservation
The choice of file formats largely depends on your needs, time horizon, and the specific purposes that digital archives and records should support.
The reasons for long-term preservation of digital archives and records can be many. A manufacturing company may, for legal reasons, need specific records to be available throughout the entire life cycle of a given product or longer, potentially spanning decades. It may also be about ensuring continuous access to vital and confidential records that are of great importance to a company’s business, such as recipes, research results, or technical data, as well as material that documents or underpins the company’s business and management decisions. There may also be purely historical reasons for long-term preservation, where the goal is simply to make the material available to future generations.
Despite (or perhaps because of) the complexity and significance of the field, there is no universal or standardized approach to long-term preservation of digital records and archives, and there are many different opinions and views on what is best to do – for example, there are differences in the strategies that national archives around the world have decided to use in connection with long-term preservation.
File formats that are suitable for long-term preservation typically have one or more of the following characteristics:
The choice of file formats can, of course, also be influenced by many other internal and external factors, including IT infrastructure, costs, and legislation. Additionally, it depends on whether the digital archives and records are born-digital or created as part of digitization processes, and whether they may contain embedded files (such as presentations with video files).
Conversion
When using file formats for long-term preservation, conversion will play a significant role.
This can involve large amounts of digital archives and records that need to be converted to ensure their future usability, but it can also be in situations where it is only at a specific stage in the life cycle of the record (e.g., at archiving) that the conversion takes place.
Although the conversion work can be largely
- Open – If formats are open, unlike proprietary file formats, they are not controlled and supported by a single developer. The format’s description will be publicly available and, in some situations, managed by a standardization body. Thus, open file formats can be more easily and continuously implemented in new programs, which also increases the likelihood of readability, usability, and compatibility in the long term. A significant example is PDF/A-1 (ISO 19005-1:2005).
- Widespread – Used across programs and platforms, as well as industries, sectors, countries, and languages. The more people use the file format, the more people will have an interest in ensuring its future usability.
- Supports adding metadata. This is essential for managing records and ensuring and maintaining integrity.
- Uses or supports lossless compression. Allows exact restoration of original, compressed data without loss of information.
| Type | Recommended File Format |
| Document | PDF/A-1 |
| Video | AVI |
| Audio | WAV |
| Image | TIFF |
| MBOX | |
| Website | WARC |
| Spreadsheet | CSV or PDF/A-1 |
| Presentation | OPT or PDF/A-1 |
| Container | ZIP (uncompressed) |