October 1997 Issue 25
Showcases - An External Perspective
We are all well aware of the value of a secure museum showcase and the protection that it can provide against physical damage to the objects displayed within it. This was recently demonstrated by an unhappy visitor to the V&A who threw a fire extinguisher at one. Fortunately, in this case the safety glass saved the day. The use of showcases for protection from adverse environmental factors is a relatively new consideration, but one that has received a lot of attention within the museum profession. The aggressive factors that must be guarded against include gaseous pollutants, insects, dust and dirt, as well as extreme fluctuations in environmental conditions such as temperature and relative humidity. Scientific reports that investigate methods to prevent, or at least minimise the degradative effects of these factors are commonplace. Research work has focussed on the examination of the construction materials and the design of the showcases, for example whether or not they should be sealed. The results of relevant studies have been brought together to produce several sets of guidelines, which aim to assist in making the most appropriate decisions, for the creation of a buffered and relatively inert environment within a showcase. The most recent guide by May Cassar 1 is a checklist, which can be of great value when choosing a new showcase.
I, an academic and a scientist on a brief placement at the V&A, was interested to find out how much of an impact this information was having in practice within museums. This was of particular interest as academic researchers are often associated with theoretical ideals with little consideration for the practical logistics and costs involved. With this in mind, I devised a questionnaire which not only requested information about the current range of showcases in use, but also attempted to survey the views and policies of museum professionals.
The first difficulty was to decide whom to survey, as the duties of museum staff are not always clearly defined. Members of 'The UK Conservation Scientists' Group', who had access to collections, seemed most appropriate and seventeen were invited to complete the questionnaire. A handful of replies were returned, of which five were completed in full.
All the individuals who replied recognised the standard considerations which minimise environmental degradation within showcases, such as the need to use inert materials in construction and dressing. In reality, however, potentially damaging environments still exist with the more traditional showcases and some more modern acquisitions. For example, wood and wood-based composites, like medium density fibreboard, were commonly quoted as being in use. Many museums had attempted to minimise the effects of such environments by using barrier methods, such as varnishes and surface treatments. In-house testing of the potential for materials to cause corrosion also appeared to be quite common.
Other specifications involved the use of sealed units with separate compartments for easy access to lights and the display envelope. In general the internal showcase environment was controlled only with adsorbent materials, such as silica gel. Externally, most galleries have relative humidity, temperature and light levels controlled to Thomson's 2 specifications with some seasonal variation. It is in this area of technical compliance that purchases are steered by manufacturers.
It is clear that most members of the group who replied were well informed of the current guidelines with respect to museum showcases. However, the dearth of valid replies, and the difficulty in some cases of gaining key information, seem to suggest the responsibility for showcases is ill-defined. That is, the matter might not be perceived to be of high enough priority for one person to be in sole charge of them. If true this is unfortunate. It could well be more cost-effective to control the internal micro-climates within showcases than the whole gallery.
Reliance on manufacturers to produce showcases with such a high specification can also be a risk, particularly if full details of the conditions and objects to be displayed are not known at the time of briefing. As the law has it, caveat emptor or buyer beware!
I am grateful to De Montfort University and The Conservation Unit of the Museums and Galleries Commission for financial support. I would also like to thank staff of the V&A Science Group for making my stay an enjoyable one.
The author is currently a lecturer and the MSc Conservation Science Course Leader in the Department of Chemistry and Physics at De Montfort University, Leicester.