Over the past few weeks there has been a fair amount of talk about archives at the Fundació. The exhibition Miró-ADLAN. An Archive of Modernity (1932-1936) has raised our awareness of the importance of the appropriate conservation of papers and documents which may not initially strike us as particularly relevant. Drawings, postcards, notebooks, newspaper clippings, tickets to concerts or exhibitions, iconic posters, opera programmes… assorted documents such as these may not only contain memories of great sentimental value, but also constitute a legacy that can be of great interest.
Anna Ferran, who specialises in preventive conservation and paper restoration, offers us a few suggestions.
Home archives have often been useful for illustrating important events and historical moments. Documents that have been kept over the years are a treasure that we must preserve for future generations.
To learn how to preserve our documents, we must first have a look at the potential causes of deterioration in order to try to identify and minimize the risks.
Causes of Deterioration and Its Effects
The causes of deterioration can be classified into two groups: damage caused by the elements in the composition of the documents (intrinsic causes) and those caused by elements external to the documents (extrinsic causes).
The intrinsic causes involve the materials in the documents’ composition, which can deteriorate because of their very nature. First of all, there is the support, which is usually paper or parchment. Paper is a plant-based material (made of plant fibres such as linen, cotton, hemp or wood) and parchment is animal-based (produced by treating sheep, goat or cow skin, primarily). Secondly, we have the elements that are applied to that support, be they dry, such as pastel or charcoal; wax-based, such as Conté crayon; calligraphic or printing ink; and water-based media such as watercolour or gouache, among others.
Iron gall ink has a corrosive effect on paper.
The extrinsic causes are related to agents that are external to the documents, but have a direct impact on them, be they environmental conditions (temperature, relative humidity, light, pollution), biological agents (insects, micro-organisms, rodents), anthropic causes (handling, staining, added metal elements, etc.) or catastrophic events (fires, floods, etc.).
The effect of these causes is the damage that appears on documents which we refer to as alterations and deterioration.
Alterations can be tearing, holes, curling, or even stains in a variety of colours; they can be caused by insects, handling, or environmental conditions.
High humidity and temperature levels can lead to chemical reactions that affect the stability of the ink or the cellulose in the paper itself. They can bring about the growth of fungi, which are capable of breaking down cellulose for its nutrients and leaving a variety of coloured stains on the paper support.
If we can identify the source of our documents’ deterioration and bring it under control, we can improve their conservation. Obviously, not all causes can be controlled, but it is within our power to minimize their impact by following a few basic conservation guidelines.
Insects bore tunnels that can cross an entire book from top to bottom.
Preserving Documents Properly
To ensure proper conservation of the documents we keep at home, we must take several factors into account.
- The Space
The best place to store documents is a stable, well-ventilated environment, but where temperature and relative humidity do not fluctuate significantly. Nearby heat sources such as air conditioning units, heaters or radiators must be avoided, as well as the most humid, exposed areas in a house (basements, garages or attics).
It is important to avoid direct natural light, and to filter it through curtains or roman blinds. Light radiation contains ultraviolet and infrared rays that cause ink to discolour or fade, also drying out and deforming supports.
The storage space and its furniture must be cleaned regularly. Dust particles that settle on objects can have an abrasive or corrosive effect, causing biological contamination. Dust on documents can collect acid vapours or humidity from the air.
Documents can be cleaned with a soft brush (with goat hair bristles), gently drawing it across the surface of the paper. In the case of photographs, given how sensitive their surface is to abrasion, an air blower is recommended.
Cleaning a family letter with a soft-bristled brush and a photograph with an air blower.
Handling is the most frequent cause of damage to documents and photographs. Rolling up or folding documents is not recommended, since it can cause bending which, over time, can lead to tearing.
Documents must be handled with clean hands, with gloves, or using paper corners to avoid staining or leaving finger marks. Corners can be made by cutting out and folding pieces of acid-free paper with rounded or triangular edges.
Handling a photograph with a triangular paper corner and examples of corners made with acid-free paper.
Whenever we have to move or ship a document we must, if possible, place it on a rigid additional support (a folder, box, or cardboard base) to avoid unnecessary creasing or bending.
In the case of books, we recommend not pressing them open too much in order to avoid stretching and damaging the sewn binding. Very few books can be opened beyond a 180-degree angle without suffering structural damage. To make it easier to open a book without forcing it beyond its specific limit, we recommend using stands, which can be made with triangles of acid-free foam board.
Atriles triangulares elaborados con cartón pluma neutro.
- Protection and Storage Elements
The best solution for storing documents is to keep them in containers that block out light, dust, environmental pollutants and insects, while reducing variations in relative humidity on the inside.
To protect and organize documents, we can place them in boxes, folders or sleeves following the groupings chosen by whoever generated or collected them. Whenever possible, it is advisable to use acid-free materials, avoid plastic, and use quality paper for documents sleeves1.
Examples of conservation boxes for photographs and books.
Materials to avoid for storing and grouping documents:
|Plastic protection||Not stable in the long run. Generate static electricity. Do not breathe.||High-quality acid-free paper. PAT-approved stable plastics2.|
|Adhesives can contain acidic materials that eventually cause the plastic or paper support to come unstuck.
They lose their adhesive qualities and generate dark stains that are difficult to remove.
|There are tapes that claim to be “archival” made with acid-free adhesives, but in the long run they create the same problems.
There is no ideal alternative.
(paper clips, staples, pins)
|Over time, they rust and can perforate the paper.||We can group the related documents in acid-free paper sleeves.|
|Rubber bands||They can soften in high temperatures and stick to the documents. Over time, they dry out and become rigid and brittle.||White cotton ribbon.|
Last of all, whenever we encounter deterioration that we are not certain about or that we believe may require a conservation/restoration effort, it is important to contact professionals in the field.
For further information:
1 Sleeves are sheets of paper folded down the middle to enclose documents.
2 The PAT (Photographic Activity Test) is an ISO standard test specified in ISO 18916: 2007, which evaluates materials according to their archival quality.