Displaying archival records
Archival records on display are subject to the effects of light, heat and humidity, as well as physical risks such as theft and vandalism. Records are also endangered by inappropriate or poor quality display methods.
It is the responsibility of the organisation or individual planning the display to assess the items and have them displayed appropriately. It is advisable to consult a professional conservator at the planning stage to determine the best way to mount and display records.
Choosing items for display
Certain formats are more vulnerable than others, and so require greater care and more stringent display conditions. In general terms, the most vulnerable materials include watercolours, photographs and handwritten documents. Oil paintings, printed documents and books are a little less vulnerable. Other items, such as those made from metal may require a lower level of care.
For further information on particular formats, see our format specific preservation advice. While not directly addressing display concerns, this information will equip you to assess the vulnerability and particular sensitivities of each type of record.
Consider exhibiting a facsimile in place of the original in the following cases:
- where the item is vulnerable, unique or valuable
- Where security is insufficient
- the item is to be displayed for an extended period.
The display environment
When assessing the display venue consider the following factors:
- Avoid direct sunlight that is very damaging.
- Artificial light sources can also be a source of damaging ultraviolet (UV) radiation and heat.
- Light sources should have a low UV output and be soft and diffuse.
- Lights should be located 2 to 3 metres away from the display items to prevent heat build-up.
- Special instruments are available to measure light levels. As a general rule, UV radiation should be less than 75 µW/lumen and light levels should be less than 100 lux. Particularly vulnerable material may require even lower light levels.
- Conservators and lighting experts can provide more advice on appropriate lighting systems.
Temperature and humidity
- Environmental conditions should be maintained around 20 °C in temperature and 50 % relative humidity, with minimal fluctuations. Some materials may require more stringent control.
- Ideally, exhibition spaces should be air-conditioned 24 hours a day, 7 days a week.
- Avoid damaging high temperature and humidity levels.
- Organic materials expand and contract with changing environmental conditions. If it happens continuously to records with paint or ink layers and composite objects such as bound volumes the physical integrity of the object can break down.
- When selecting an exhibition venue give consideration to the location potential sources of harm such as water leaks, flood, fire and air pollution.
- Food preparation areas should be away from exhibition spaces, as they are a common source of fire and flood, and tend to attract vermin and insects.
- An exhibition area should ideally be a dedicated room. Corridors and other thoroughfares do not usually serve well as exhibition spaces as heavy human traffic can contribute to the risk of damage to displayed objects.
- Exhibition spaces should be cleaned regularly to check for sudden insect or mould problems. Display objects should be examine to ensure they have not been harmed by the display conditions or damaged by visitors.
- Display supports mounts and display tables should be checked routinely to ensure they are undamaged and are continuing to function correctly.
Display methods and materials
The way exhibit items are mounted and displayed will vary according to their nature and the exhibition design. The selected method must conform to preservation principles in order to provide the maximum protection for the display items:
- Never exhibit an item without some form of protection, such as a frame with glazing or a display case. This will shield the item from dust and dirt and reduce the item's exposure to UV light. Frames and display cases also act as a security measure by providing added protection against damage and theft.
- Items exhibited in frames should be window matted to museum standard.
- Use custom designed cradles or brackets to support three dimensional items such as volumes, models and sculptures safely.
- Only high quality, chemically inert materials should be used in the construction of display cases, mounts, frames and other display devices. Materials to avoid include acidic cardboard, unsealed wood, rubber adhesives, chipboard, PVC plastic and sticky tape.
- Sometimes purpose-built display cases are constructed for an exhibition. Before display items are installed, time must be given for the coatings and adhesives used to fully cure and off-gas to prevent damage by volatile solvents. Protein-based materials such as wool, silk and animal glue should also be avoided as they attract insects.
Security is an important aspect of a display, particularly when the display will be open to the public. The level of security should be appropriate to the value of the items on exhibit. The mounting system should protect the display items from accidents, vandalism and theft. Consideration should be given to the use of other security measures such as security guards, cameras and alarm systems, both during and after operational hours.
Duration of display
Even in the most strictly controlled display environment, items are still subject to damage to some extent, mainly through light exposure. When planning an exhibit, it is important to consider that the longer the display period, the greater the potential for damage. Most items will show some degree of fading, yellowing or weakening when displayed continuously.
Display periods should therefore be kept short, say to three months at the recommended light levels. Since light damage is cumulative, display can be extended if the item is particularly robust, or will not to be displayed again for a lengthy period. It is often necessary to display particularly vulnerable material such as watercolours and some photographs at very low light levels. If the display system includes light limiting techniques such as curtains or timer switches, these materials can remain on display for a longer period.
Some materials, such as certain 19th century photographs, magnetic tapes and thermal faxes, are so vulnerable to light damage that they should never be displayed in their original form, and should be substituted with a facsimile.
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