Displaying any material can be risky. The material is subject to the effects of light, heat and humidity, as well as physical risks such as theft and vandalism. Also, if the display method is inappropriate or of poor quality it can endanger the material.

Whether a priceless oil painting or a college diploma, all items are subject to the same influences while on exhibit. It is up to the organisation or individual planning the display to assess the items and display them appropriately. A professional conservator should be consulted at the planning stage when items of unusual fabrication or significant value are going to be displayed. 

When selecting items to display, consider their susceptibility to damage. Certain formats are more vulnerable than others, and so require greater care and more stringent display and handling conditions. Other items, such as those made from metal, are robust and require a lower level of care. In very general terms, the most vulnerable materials include watercolours, photographs and handwritten documents. Oil paintings, printed documents and books are somewhat less vulnerable.

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.

In some cases, it is worth considering exhibiting a facsimile in place of the original, eg if the item is extremely vulnerable, security is insufficient, or the item is to be displayed for an extended period. The facsimile could take the form of a photograph, a colour photocopy, or a hand-drawn copy produced by a calligrapher or an artist.

Part of the process of planning a display, is the assessment of the display venue to ensure it has no features that could endanger the exhibit items. Factors to consider are as follows.

Lighting

• Direct sunlight is very damaging and should be avoided.
• Artificial light sources can also be a source of damaging ultraviolet (UV) radiation and heat.
• Ordinary fluorescent lights tend to have a high UV output unless they are purposely filtered, and incandescent lights can create a heat build-up. Light sources should be soft and diffuse, rather than direct and intense, and should be located 2 to 3 metres away from the display items.
• Special instruments are available to measure light levels. As a general rule, UV radiation should be less than 75 microwatts/lumen, and illuminance should be less than 100 lux. Particularly vulnerable material may require even lower light levels. Conservators and lighting experts can provide more advice about appropriate lighting systems.

Temperature and humidity

• Ideally, exhibition spaces should be air-conditioned 24 hours a day, 7 days a week.
• High temperature and humidity levels can be damaging, and therefore should be avoided. Levels should be maintained in a range suitable for human comfort, which is around 20°C in temperature and 50% relative humidity. Variations of around 2°C and 5% respectively are acceptable, however some materials may require more stringent control.
• Strong fluctuations in temperature and humidity should be avoided. Most organic materials expand and contract with changing environmental conditions, and if this happens continuously it can lead to stresses and distortions, and ultimately the breakdown of the physical integrity of the object. Regular variations are particularly dangerous for objects with paint or ink layers, and for composite objects such as bound volumes, as the adhesion of the layers can break down.

Location

• Exhibition areas should be located so as to minimise the effects of potential disasters such as water leaks, floods and fires.
• Food preparation areas should be kept well away from exhibition spaces, as they are a common source of fire and flood, and tend to attract vermin and insects.
• When selecting an exhibition venue, give some consideration to the location of other potential sources of harm. For example, a nearby carpark may create air pollution inside the display area, or toilets located overhead on the next floor could create a water leak.
• 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 accidental and deliberate damage to displayed objects.

Maintenance

• Exhibition spaces should be cleaned regularly. This provides an opportunity to check for sudden insect or mould problems, and to examine display objects to ensure they have not been stolen or damaged by visitors, and have not been harmed by the display conditions.
• Display equipment, such as supportive mounts and display tables, should also be checked routinely to ensure they are undamaged and are continuing to function correctly.

The way exhibit items are mounted or otherwise displayed will vary greatly according to their nature and the design of the exhibition. Whatever the selected method, it must conform to certain preservation principles in order to provide the maximum possible 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, if UV-filtering materials are used, also 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, polyvinyl chloride and sticky tape. Proteinaceous materials such as wool, silk and animal glue should also be avoided as they attract insects.

Even in the most strictly controlled display environment, items are still subject to damage to some extent, mainly through light exposure. The longer the display period, the greater the potential for damage, and it is important to consider this when planning an exhibit. Most items cannot be displayed continuously without suffering some degree of fading, yellowing or weakening. Display periods should therefore be kept short, or the display items rotated so as to minimise the damage.

The National Archives of Australia aims to display all material for only three months out of any year. This three-month limit can be waived under certain circumstances: if the item is particularly robust; if it is not to be displayed again for a lengthy period; or if the display system includes extra light-limiting techniques such as curtains or timer switches. To enable particularly vulnerable material such as watercolours and some photographs to remain on display for as long as three months, it is often necessary to display them at very low light levels.

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.

Further information on displaying archival items can be obtained by contacting the Agency Service Centre.

Follow this link obtain this advice in PDF format.