7 Deterioration / wear and tear
Deterioration and wear and tear constitute a more gradually evolving threat to which artworks and cultural property are exposed. This is barely discernible on a day-to-day basis, and is often only noticed when comparing images documenting the condition of objects over long time intervals. However, deterioration need not necessarily simply be accepted fatalistically as a logical consequence of the use of cultural property as a source of information, exhibit or visitor attraction. In many cases, greater awareness and simple measures can help to minimize such damage.
What do we mean by the use of cultural property and by wear and tear? The focus here is on the use of cultural property which is accessible to the general public, such as historic buildings, art collections and archives. The type of use depends on the particular type of cultural property concerned, whereas wear and tear can be attributed to a few causes which occur individually or in combination, as shown in Table 1.
Table 1: Correlation between type of use and wear and tear
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A high level of use confirms the significance society attaches to the cultural property in question. If we understand our cultural heritage to be a resource, then we should welcome its sustainable use. This must not, however, be allowed to escalate into consumption, but must be carried out considerately and purposefully with an eye to the interests of future generations.
Historic buildings and their furnishings
Simply walking around a building causes gradual wear on floors, stairs or handrails. Paneling or doors are also at risk from unintentional scuffing by clothing or bags. At first the abrasion only affects the surface, but then it progresses into the base material itself. Particularly heavy use can even cause damage to the base structure. If a floor is especially valuable, the walking area will require specific individual protection. However, it is not solely the mechanical deterioration caused by direct contact with shoes and hands that is significant, but also the dirt they bring in from the outside. Fine dust is spread throughout the institution, while bigger particles of dirt remain on the floor where they are rubbed by shoes with a sandpaper-like action. A high visitor footfall will necessitate cleaning at more frequent intervals, which in turn represents a further deterioration factor – especially if cleaning agents and methods are used which, although convenient, are unsuitable from a conservation standpoint (Fig. 1). Special dirt-trapping floorings in entrance foyers are effective ways of reducing the amount of dirt brought in. However, a specific care and maintenance concept should also be in place.
Fig. 1: Wiping the marble mantelpiece with a damp cloth has worn away the gold leaf on the mirror frame
Construction work in historic buildings and museums poses a major problem as staff and contractors are often not sufficiently aware of the issues involved. Aggressive mineral dust produced as a result of building work spreads through whole tracts of a building and is deposited on sensitive surfaces. This can then only be removed – if at all – by trained restorers. Any movable cultural assets should be removed from the danger zone prior to any construction work, and fixed objects should be protected by thick enclosures. Advance planning should make provision for the strict separation of dirty and clean zones, with dust curtains and damp floor mats between them.
As well as tours, listed buildings sometimes also play host to events, receptions and concerts or are used as sets for filming and photoshoots. While the additional income can help to finance conservation measures, there is also a risk that the building will be harmed because a space usually designed to be used by a small number of visitors is often not suitable for a large volume of people (Fig. 2). Too many visitors increases the risk of deterioration, while at the same time a lack of awareness, distraction by the various activities going on or a relaxed mood can lead to careless behavior when using the historic fabric and consequently result in damage to the building and its furnishings. Especially bad are excessive numbers of chairs, temporary fixtures, decorations and candles, the preparation and eating of refreshments (buffet, drinks), as well as the impact on the room climate (heat radiated by lamps and large groups of people, as well as the damp vapors they give off). Before taking steps to increase visitor numbers, therefore, conservatorially sound usage concepts must always be developed. With a clearly formulated framework that takes account of the conditions for each room, guests can be made aware of the issues and damage can therefore be avoided.
Fig. 2: Large throng of visitors in the bedroom in the Amalienburg pleasure palace in the grounds of Nymphenburg Palace, Munich
Table 2 provides an overview of the various ways in which historic properties are used and the types of damage caused.
Table 2: Wear and tear in historic properties
| Property | Type of use | Causes of wear and tear |
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Sculptures, statues and other monuments situated outdoors constitute a separate issue. Although deterioration also poses a risk here, far greater threats are deliberate damage (vandalism), exposure to the weather and the impact of air pollution, or even theft (in particular the theft of metal sculptures from public places has greatly increased as a result of rising material prices). See also the other relevant sections of the SiLK guidelines for more information.
Exhibitions
Exhibiting is one of the core purposes of museums. However, exhibition galleries often have environmental conditions that impact negatively on the conservation of the exhibits – one need only point to the level of lighting required to view them. There are therefore some unavoidable conflicts between conservation goals and exhibiting. When arranging exhibitions – which includes their handling, shipping, mounting and hanging – it is therefore necessary to minimize the risk of mechanical deterioration (Table 3 gives an overview of the most frequent causes of deterioration in an exhibition setting).
Is an object in an exhibitable state? Can it be transported? Are there any weak points in its construction? What environmental conditions are necessary and need to be created from a conservation point of view? Answering these questions is vital in order to avoid causing deterioration when mounting exhibitions.
Cultural artifacts can easily be harmed by incorrect handling. If their surface is touched by bare hands, perspiration on the hands will promote corrosion and bind dirt (Fig. 3, Fig. 4), while thin mounts, such as poliment gilding for example, are quickly worn through if they are repeatedly touched. Damage of this type can be avoided by wearing gloves. Careless touching can not only break fragile objects, it can also result in structural parts being broken off, even if these did once serve as a grip, handle or carrying strap.
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| Fig. 3: Polished bronze sculpture | Fig. 4: Frequent touching with bare hands has left corroded fingerprints on the sculpture |
Much damage results from the use of inadequate protective packaging for shipping purposes. If rough materials are used to wrap objects, or nothing at all, there is a risk of scratches or scuff marks. Items with inadequate padding may be broken or deformed as a result of vibration or knocks. Three-dimensional exhibits need to be mounted properly for the duration of an exhibition. If they are not supported appropriately, there is a risk of irreversible deformation due to their own weight (Fig. 5). To avoid such accidents, floor-standing exhibits should be provided with a surround or presented on a pedestal (cf. also Accidents/malfunctions section).
Fig. 5: Presenting this Bible (ca. 1790) in a display case that is too small has resulted in a kink in its cover
Many exhibition visitors confuse touching – despite being forbidden – with holding. They think their own touching is one single, harmless act, but cumulatively it results in abrasion and chemical contamination. It is therefore advisable to protect particularly vulnerable objects by placing them in display cases, behind glass, or behind a distance barrier. The haptic desires of visitors can be indulged by means of special didactic tools such as hands-on stations (with reproductions or artistic techniques that can be touched), without harming the originals (Fig. 6, Fig. 7). To draw their attention to such matters, signs pointing out rules for visitors should be displayed in the entrance foyer.
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| Fig. 6: Hands-on station with various strips created using historical techniques | Fig. 7: Replica of chainmail shirt for visitors to touch |
Technical artifacts and kinetic artworks constitute an exception as in this particular case motion is essential for appreciating and understanding them. For the most part, however, movement also entails wear. In this case, individual solutions must be identified, which could range from limited operating time (using timers or motion detectors) through to replacing the parts subject to wear.
Table 3: Deterioration of exhibits
| Exhibit | Type of use | Deterioration of exhibits |
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Caring for archives
Without access to collections of photographs, files, maps, plans and other documents, it would be difficult or perhaps even impossible to fully understand past events. Archives play a key role in the reconstruction of historical relationships. However, the value of archive materials stands and falls with their systematic recording – this includes recording collections while maintaining their original order and relationships, indexing, retrieval means, and not least their orderly filing and storage.
The original owners of documents often used binding materials that aged quickly, and consequently may damage such archive items. For instance, metal staples and paperclips corrode, discolor paper and eventually break at the slightest pressure, such as when turning over a page. Documents may then become disarranged and their sense obscured, and they could consequently lose their value as the historic record. The same is true of rubber bands when they get brittle and tear. However, they can also soften, in which case they act like a spot of glue between documents. If one attempts to separate them, parts of one document can easily tear off and remain stuck to the other one. To prepare archives for use, therefore, such impermanent materials should be replaced by durable ones (thread binding, parchment envelopes, folders made of acid-free card etc.).
Archive materials suffer from frequent use, but even more so from inappropriate handling. Even touching with clean hands transfers perspiration from the hands, the acid content of which often causes irreversible chemical changes. For this reason, gloves should always be worn when handling historical film and photographic materials (Fig. 8). Old, wood-containing papers can be so brittle that they tear or break even when handled gently. If the original materials are to be kept long term and if the information they contain is to continue to be accessible, microfilming or digitization is therefore the safest solution for very old or especially valuable documents.
Fig. 8: Handling of historic photographs with cotton gloves
The more accessible a collection is, the more easily it can be studied. For this purpose, in addition to the above-mentioned retrieval means, spacious desks with good lighting are just as important as the ability to make copies or reproductions. Before using an archive, visitors should register and declare their research interests. Overall, these measures will avoid users becoming frustrated and will reduce the risk of deliberate damage or even theft. To minimize damage caused by carelessness, the consumption of food and drink should not be permitted in reading rooms. Careful handling is best supervised in a users’ room. Loans of original archive materials should therefore only be considered in exceptional circumstances and should be restricted to exhibitions in the charge of conservators. Table 4 below lists examples of archive materials and their use, and summarizes the potential wear and tear.
Table 4: Deterioration of archive materials
| Archive materials | Type of use | Deterioration |
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Photos: Christoph Wenzel