Teachers' resource: Museum conservation
This resource looks at conservation in the museum environment. It contains suggestions for activities that are adaptable for the Science and Design & Technology areas of the curriculum at Key Stages 2 and 3. They can be done either at the Victoria and Albert Museum or at school. Activities include:
- Conservation issues
- Human beings
- The atmosphere
The above activities are supported by the section that looks at the causes of deterioration and decay and there are further reading resources and useful links.
The V&A houses some of the nation's most important and valuable treasures and has a duty to ensure that these objects are preserved for the benefit of future generations. The museum is in the vanguard of research into new methods of conservation and enjoys a worldwide reputation as a centre of excellence. It offers students a unique opportunity to explore how a huge range of objects, spanning most periods of history, are cared for and preserved.
All the activities develop students' skills in scientific investigation and expand their understanding of the processes of decay and chemical change, the properties of materials and the behaviour of light. The resource addresses some of the designing and making elements of the Design & Technology curriculum as well as the cross-curricular themes of environmental education and education for citizenship.
The activities concentrate on three contrasting galleries. The 20th Century gallery (Rooms 70-74) is a good example of the extent to which the need to conserve collections now influences every aspect of gallery design. The Renaissance galleries on Level 1 are more traditional in appearance but confront the conservator with just as many problems, such as how best to preserve large monumental pieces not kept behind glass. The new Sculpture gallery (Room 111) contains examples of different materials and techniques, and is a good place to start thinking about the conservation issues associated with particular materials.
A scientific approach
If students are encouraged to adopt a scientific approach during their visit to the museum, they will learn more and gain a greater understanding of scientific concepts. One of the best ways of ensuring this is by asking open-ended questions. Students will then be required to make detailed observations, gather evidence and use the information gained to make predictions, formulate hypotheses and solve problems. This approach will challenge older or more able students while allowing the younger or less able ones to make valid contributions at their own level. It is also important for students to generate their own questions during a visit and determine how they might be answered.
What is museum conservation?
All materials, whether natural or manufactured, are continually changing. All around us there is evidence of this unavoidable process: rotting wood, rusting steel, weathered buildings. Nothing can be done to halt this; it can only be limited. In a museum, the indications of decay are less extreme than in the world outside but they are still there.
The term 'conservation' refers to both preservation (or stabilisation) and restoration (or consolidation). Preservation usually relies on controlling factors such as light or humidity that might damage an object by spoiling its appearance and reducing its life span. Ideally, objects should be preserved in the state in which they were acquired by the museum. When fragile materials deteriorate, however, the strength of an entire object can be jeopardised. It may then become necessary to carry out restorative work.
Restoration may require parts to be replaced or added. Sometimes the aim of restoration is to make an object look like new. This is not generally the case in museums, where conservators go to considerable lengths to ensure that new work on an object is carefully documented and can be easily identified.
To help students engage with these issues, ask them if they have any treasured possessions that they treat particularly carefully. Ask them how long they would like their special objects to survive. How do they care for them? What precautions do they take when handling or using them, and how do they store them when not in use? What sort of places or under what conditions would they not keep their object, and why?
Causes of deterioration and decay
In a museum the factors that are most damaging are light, the environment (temperature, humidity and the quality of the air) and the presence of living organisms, such as humans and insects. Although each of these can operate independently, their effects are more pronounced when they work together. Students are likely at first to identify individual causes of decay, but as their understanding of the processes involved grows, they will become aware of the relationship between the various factors: an unscreened window will allow in light, which may discolour objects, as well as the heat of the sun's rays, which can cause further damage.
Light is a form of energy that can cause irreparable damage to objects. Materials derived from plants or animals are particularly affected by light: dyes and pigments change colour and the physical structure of the material can be weakened, eventually causing it to disintegrate. For this reason, the lighting of many of the displays in the museum is kept at a low level.The amount of damage that light causes depends on the type of light and the materials from which the objects are made. Natural light is the most harmful as it contains the highest proportion of ultraviolet radiation. In the 20th Century gallery the windows are covered with a thin plastic film containing minute particles of titanium which reflect a large proportion of the incoming light and filter the ultraviolet rays. These are supplemented by mesh blinds, which reduce the light level still further.
Lighting levels are fixed according to the objects on display, and where the cases contain objects in mixed media then light levels are fixed at levels appropriate for the most sensitive object. In Rooms 21 and 21a of the Renaissance 1200-1650 galleries, mesh blinds are used to cut down the level of natural light in the rooms. Artificial lighting is provided by halogen spotlights, which are the closest approximation to natural light, and fluorescent tubes.
The British Galleries have been recently designed with very close attention to conservation concerns. The conservation department advised on display materials and methods, also on environmental issues and special requirements for vulnerable objects.
The quality and composition of the environment, which covers temperature, humidity and pollution, are critically important to the conservation of objects. On its own, temperature is the least important factor, although rapid changes can cause damage, especially when objects are made from a variety of materials which expand at different rates. Too high a temperature will also accelerate some chemical reactions.
For these reasons every effort is made to maintain an even temperature in the museum. Conventional radiators provide heating in the galleries during the colder months of the year so it is important that objects are not placed close to or above these. The effect of the sun as a source of direct heating also has to be considered. Blinds and protective films that reduce light levels perform a vital secondary function in that they also reduce solar heating. An additional source of heat is provided by visitors: ten visitors generate as much heat as a one-bar electric fire.
Temperature becomes more important in relation to relative humidity (the amount of water in the air). Relative humidity is measured by comparing the actual amount of water in the air with the maximum amount that the air could hold. It is expressed as a percentage.
Fluctuations in relative humidity can cause objects to change dimensions, while high levels of humidity also encourage the growth of moulds. Some materials that contain water, such as wood, paper and fabric, behave like sponges, absorbing water when the air is dry. Wood swells when it becomes damp but, surprisingly, fabrics generally appear to shrink. In fact, the fibres of fabrics do swell as they absorb water, but this is across the grain and has the effect of tightening the twist of the threads thereby causing shrinkage.
The V&A therefore tries to maintain relative humidity at a constant level. This is not an easy task, as visitors exhale water vapour and in winter the building needs to be heated. Some display cases contain a tray of silica gel to absorb excess moisture. This poisonous substance, which is often found in the packaging of electrical equipment, has the ability to absorb many times its own weight of water. Saturated crystals of silica gel can be dried and reused.
The V&A is also equipped with an estate-wide system for collecting, storing and disseminating environmental data relating to objects. It is called OCEAN and can be accessed from a networked PC. You will see free-standing sensors either inside museum display cases or wall-mounted next to exhibits. These sensors deliver information on the current temperature and relative humidity.
To reduce air pollution from outside the building (mainly traffic fumes), windows and external doors are kept closed wherever possible. Because of limited resources, the museum has decided to use air conditioning only in selected galleries and temporary displays. The best possible protection against atmospheric pollution is provided by the new display cases in the 20th Century gallery. They have reduced the rate of the exchange of air to a complete change only once every ten days. The air exchange rate of the old style of glass cases with wooden frames can be more than ten times higher.
The V&A is presented with a genuine dilemma: it wants to encourage people to enjoy the objects in its care, but visitors pose a real threat to the very objects they come to admire. The presence of living, breathing human beings affects both relative humidity and temperature in the galleries, upsetting the delicate balance necessary for the preservation of the objects. Humans also leave behind clothing fibres, hair and skin, which all feed the insect population.
Also, although it is a natural response to want to touch things, the museum usually has to discourage this as the cumulative effects of abrasion, grease and sweat can result in irreparable damage. The China and Korea galleries, however, have specially selected objects on display for visitors to touch. The British Galleries also have a series of interactive areas and some objects that can be touched. Particularly vulnerable materials and objects are protected by glass cases, in which the atmosphere can be controlled. Larger or more robust objects on open display have to rely on other methods to deter the public from touching them. In the 20th Century gallery there are notices reminding people not to touch objects. Some sort of physical barrier, such as a rope or plinth, may also be used. These passive systems are reinforced by warders who watch the objects and politely remind visitors of the rules.
Many of the objects on display are extremely valuable. Security therefore has to be a prime concern. Galleries are laid out so that warders have good views of all the objects and visitors. In addition, especially valuable objects are further protected by sophisticated electronic alarm systems.
The effects of fire are often devastating and various measures are taken to minimise this risk. Extinguishers are sited at strategic points in the galleries and an electronic fire detection system ensures swift action can be taken in the event of an outbreak of fire.
One of the most serious offenders is the carpet beetle. It is the larvae, or 'woolly bears' as they are called, that cause the damage, feeding on anything that contains wool, leather, fur or feathers. Clearly, they have no respect for the value or antiquity of an object and are just as happy to feast on a 17th-century tapestry as they are on the felt lining of a display case!
Since 1990, as a part of the museum's strategy for insect pest management, there has been a successful detection and monitoring programme. Restricting the potential food source is an important element in the programme. In the past, felt was widely used to line display cases, but its high wool content provided the perfect meal for carpet beetles and it is now being replaced by synthetic materials when possible. The introduction of a good cleaning programme in the museum has also helped reduce the levels of insect activity.
Small triangular prisms made of white cardboard are carefully positioned around the galleries and in some display cases. These are insect traps, used to monitor the current population of two species of carpet beetle. The base of these traps is covered with an adhesive to which crawling creatures stick. Unfortunately, though, the traps catch harmless creatures and potentially useful ones such as spiders. The traps are usually located in corners close to the skirting board, although some are hidden beneath fabrics. One, for instance, is tucked beneath a red chaise longue, since the beetles apparently are drawn to that colour. Most of the traps are visible but it is most important that students do not touch them.
Other insect pests also pose threats, among them plaster beetles, clothes moths, woodworm and silverfish (which feed on paper). Evidence of insect damage can be seen on the lower section of the large sculpture of Venus and Adonis, in an alcove by the stairs at the end of the Sculpture gallery (Room 111). If you look carefully, you should be able to see tiny holes in some of the wood - evidence of past damage by woodworm. The sculpture, carved from limewood, has also been damaged from handling, restoration and environmental changes.
All flowers and plants should be sprayed before they are brought into the museum as this prevents insects from being carried in with them.
The new display cases in the 20th Century gallery make it virtually impossible for insects to gain access. As an added precaution, some textiles and other organic objects are treated by freezing, which kills all stages of an insect's life-cycle but causes no harm to the fabric itself.
Before your visit
Students will need to know that air contains water vapour and that when warm, moist air is cooled, it releases some of that water vapour in the form of minute droplets of water. Students might also think about the effect that extremes of temperature have on various materials: wooden furniture placed close to a source of direct heating, for instance, may buckle; clay pots subjected to frost may crack.
At the V&A
When visiting the V&A, your students could use a digital thermometer to compare air temperature in different galleries, within different parts of a gallery, and at the beginning and end of the visit. LCD strip thermometers, though less accurate, can also be used. They could also investigate how the galleries are heated and what is done to limit the heating effect of the sun.
What might cause the temperature in the galleries to change? Are objects in cases as liable to damage from changes in temperature and humidity as those on open display? You could ask students to predict the materials that are likely to be most affected by changes in temperature and humidity. Suggest that they look out for the OCEAN sensors in cases or on the walls.
Back at school
Students could make a simple hygrometer to measure the dampness of the air. They could investigate temperature changes in the classroom, taking measurements before school starts when the room is empty and at regular intervals throughout the day. They will need to record any factors that might influence the recorded temperature, such as open doors or windows. Ask students to draw some conclusions from their results.
Students could predict which materials they think could be damaged by damp air. They could conduct an investigation to discover which of their predictions were correct.
For this you will need some screw-top jam jars. Place a wad of damp cotton wool at the bottom of each. Collect a number of small objects made from different materials (say, a steel screw, a postage stamp, a wooden cube, a square of blotting paper, a plastic counter, a piece of fabric).
Place each object on a small plastic lid and rest it on top of the cotton wool. Screw the lid on the jar tightly. Keep the jars in a dark place where the temperature is fairly constant. Look at the jars every day for two weeks and record any changes you notice in the objects. Make sure that you dispose of the jars and their contents safely at the end of the experiment.
At the V&A
The V&A regularly lends objects to other museums for special exhibitions.
Choose an object that you believe could be damaged if it were lent to another museum. How might it be damaged? How do you think the object might be packed for transport? Do the people of Glasgow or Belfast or Cardiff have as much right as Londoners to see the object in their home town?
Make a list of reasons for and against moving the object. Tell students that they have been put in charge of lending objects to other museums for exhibitions. Ask them to draw up a list of rules they would make to safeguard the objects.
Imagine it has been decided to take the altarpiece in Room 25 off public display so that it can be conserved. How would students ensure that visitors to the museum knew about the object and were able to appreciate it even though they could not see it?
The 20th Century gallery has become very popular. At times the gallery is so crowded that it is difficult to see the displays. Imagine it has been decided to limit the number of people in the gallery at one time. That could mean that some people who wanted to see the displays might not be able to do so. Ask students to suggest how the numbers of visitors might be controlled and what criteria they would use to decide who is admitted.
If lighting, atmosphere, insect pests and people cause so much damage, why put objects on display in the first place? Discuss whether it would be better to keep them in a special room where optimum conditions could be guaranteed. The objects would survive for much longer.
In a world where resources are limited, would it be better to look after the homeless, rather than old things in a museum? Students could discuss this proposition and decide whether they are for or against it. They could then design a poster to put across their point of view.
In the China and Sculpture galleries (Rooms 44 and 111) there are objects for visitors to touch. Ask students to debate whether they think this is a good idea or not and take a vote on whether it should be extended more widely at the V&A.
Before your visit
Ask students to brainstorm ways in which objects at home or in school can be damaged by people. They could make a collection of objects (old coins, books, board games, etc) that show evidence of excessive handling, and then suggest ways of protecting them or limiting the extent to which they are touched.
At the V&A
Students could carry out an audit of the methods used to discourage visitors from touching objects, getting too close to them or damaging them. Can they suggest any other methods? Which methods do they think are the most effective?
Is the wording of signs important? Which of those in the museum do they think is most successful at curbing people's desire to touch? Can they improve on them?
Where in the gallery would students stand to get the best view of visitors? Does the warder remain in one place or move around? How does the layout of the galleries help to protect the objects?
Students could make a study of visitors. This would need to be handled sensitively to avoid upsetting other visitors. Nevertheless, careful observation could reveal much valuable information about how people move about the galleries, whether they read 'Do not touch' signs and which objects they stand closest to.
'Samson and the Philistines', Vincenzo Fogini, 1749. Museum no. A.7-1954 (click image for larger version)
Present students with a problem: the sculpture of Samson and the Philistines by Vincenzo Foggini in Room 21 is being damaged. People are standing too close to it and some are even touching it. What would the students do to protect it?
Back at school
Display cases offer objects a degree of protection. Students might design a new display case, to contain school trophies perhaps. They will need to consider security, the most appropriate materials to use, the height of the case (so that small children and wheelchair users could view the contents) and how it could be opened to rearrange the display.
Students could design a simple security alarm that is activated either mechanically or electrically. For the latter they could use a tilt switch, a photoelectric sensor or make their own simple pressure-sensitive switch.
Before your visit
Students could find out about common household pests and the damage that they can cause. They could select one of these organisms to study in greater depth. They could make a collection of found materials that have been attacked by living organisms, such as paper, wood, fabric and carpet.
At the V&A
Students could identify those objects most at risk in the galleries at the V&A. Students are highly unlikely to see any insects during their visit and they might try to account for this apparent absence. They could record the location of the insect traps and perhaps suggest alternative locations.
In the Jameel Gallery of Islamic Art, Room 42, carpets and textiles are contained within glass cases. Students could propose reasons why they are displayed in this way.
Back at school
Students could design and make a device to trap insect pests. It should be inconspicuous to visitors and safe for curators and conservators to handle.
Before your visit
Discuss how light is controlled, at school or in the home, with curtains, blinds or tinted glass. What forms of artificial lighting are used? Is the level or direction of illumination controlled (by shades, reflectors, dimmers, etc)? Students could draw up a list of the materials most likely to be affected by light and draw come conclusions. They could also collect evidence of the change brought about by photochemical action, such as old yellowing newspaper.
They could make a simple light meter and use it to make approximate measurements during their visit to the V&A.
A simple light meter
Cut a strip of greaseproof paper (or low-grade tracing paper) 3 cm wide and 20 cm long. Cut a second strip the same width but 1 cm shorter (19 cm long) and glue it to the first strip at one of the short ends, making the edges line up.
Cut 10 more strips, each 1 cm shorter than the previous one, and glue them together to make a long thin sandwich. At one end the sandwich will be 12 strips thick, at the other end only 1.
On the back of the longest strip, starting at the thinnest end, write the numbers 1-12 in the middle of each overlap. Write the numbers in reverse so they can be read from the front. Hold the light meter in front of your eyes and record the highest number that is clearly visible. If the whole sequence of numbers is visible, reduce the amount of light getting through by gluing a strip of coloured cellophane to the longest strip. The meter is easiest to use if fixed across the open end of a cardboard box and viewed by looking through the opposite end of the box.
At the V&A
Students could investigate the lighting levels in various parts of the galleries and try to explain why differences occur. They could propose reasons why some displays are lit directly (furniture in the 20th Century gallery) and others have no direct illumination (fabrics, prints and drawings in the 20th Century gallery).
Their investigations should allow them to guess which materials and types of objects will be lit at very low levels. They could consider whether the colour of the walls affects the general level of illumination. What would be the effect of painting the walls black?
Students could use the light meters they have made to compare light levels in different parts of the galleries. More accurate measurements can be made using photographic or digital light meters. They could then examine how the daylight is controlled or excluded, suggest reasons for this and contrast the different methods employed.
Back at school
Challenge students to design a lamp that can direct light onto a small area, using a battery and bulb. They will need to consider whether it is necessary to use any type of reflector and if it would be an advantage if the bulb could be moved within the housing to adjust or spread the light. More able students might want to experiment with lenses and even attempt to control the brightness of the lamp, either mechanically (by using a simple shutter device) or electronically (by using a variable resistor).
Students could set up a fair test to investigate the effect of natural light on a range of materials. Some objects in the museum rely on reflected light as their main source of illumination.
A variable resistor
Diagram for making a variable resistor