Three essential principles for preventive conservation in archives
Preventive conservation brings together the measures that help reduce the risk of deterioration before damage occurs. In archives, where collections are often large and made up of different materials, three principles stand out as a starting point. How they are applied depends on the materials, their condition and the risks identified in each building.
1. Environmental stability
Maintaining appropriate temperature and relative humidity is fundamental to long-term preservation. Limiting fluctuations helps reduce the risk of physical and chemical deterioration, such as the expansion and contraction of materials, or the acceleration of chemical reactions that weaken paper and other supports.
What counts as "appropriate" is not the same for every collection. Paper, parchment, photographic materials or magnetic media have different needs, and the building itself sets limits on what can be achieved. Monitoring the environment over time – rather than relying on a single reading – helps to understand how storage areas actually behave across the seasons and to decide, where necessary, which adjustments are worth making.
2. Appropriate archival storage
Selecting chemically stable, conservation-grade enclosures and storage materials helps protect collections from environmental pollutants, physical damage and deterioration. Boxes, folders and envelopes act as a first barrier against dust, light and handling, and can help buffer short-term changes in the surrounding environment.
Still, the choice of materials should take into account what is being stored. A conservation-grade material does not, on its own, make an enclosure suitable for every type of document. Format, size, weight, condition and how often the items are consulted all influence the most appropriate solution. Shelving, the way boxes are arranged and the care taken in handling are just as important as the enclosure itself.
3. Integrated pest management
Routine inspections, environmental monitoring and preventive measures help identify pest activity early and minimise risks to collections. Integrated pest management favours prevention: keeping spaces clean, controlling entry points, monitoring with traps and recording what is found, and checking incoming materials when appropriate.
When there are signs of infestation, the response depends on the species involved, the extent of the problem and the materials affected. In some cases, non-chemical treatments such as anoxia may be an option, always after assessing whether they are suitable for the objects in question.
A proactive, consistent approach
Effective preservation relies on a proactive, consistent approach to collections care. These three principles work best together and as part of a regular routine, adapted to the reality of each institution.
At EXPM, we apply these principles through tailored preventive conservation strategies, supporting the long-term preservation of archive, museum and library collections. Our work includes preventive conservation and consultancy, integrated pest management, anoxia treatments, training and conservation materials.
To find out more about our work, visit expm.com.pt, explore conservation materials at expmstore.com, or contact our team to discuss the needs of your collection.
Keeping History Alive.