Collection care includes all the measures taken to preserve the museum’s collections so that today’s visitors, as well as tomorrow’s, can see, enjoy and learn from them.
It involves understanding how agents (such as light, humidity, insects, mould) and actions, such as poor handling, contribute to the deterioration of objects, and devising ways of controlling them to reduce their effects. Our first line of defence is through simple measures, such as careful building maintenance and good housekeeping, environmental control and the effective management of pests.
Good housekeeping is part of collection care. It involves keeping objects free of dust and keeping away museum pests, such as insects which feed on objects.
Museum housekeeping can be as simple as ensuring visitors walk over doormats to help keep floors clean, to protecting objects in well designed show-cases. Our main house-keeping approach includes:
- Maintaining and improving the building
- Cleaning and controlling dirt
- Physically protecting collections
- Carrying out condition surveys
Museums are large buildings and, like big houses, they contain spaces where dirt, heat, high humidity and pests can build up and combine together to cause damage to collections. These can cause problems in the public display areas where opening doors, large windows, artificial lighting, heating equipment and the movement of people can all play a part.
Maintaining the building
The museum building is the outer envelope that protects the collections from the elements. Buildings often need to be adapted to keep the internal conditions stable. Having good roof insulation, an effective damp course, double glazing and a double layer of self-closing doors to minimise air-changes can all help.
Measures being taken at RAMM to make the internal environment safer for the collections include:
- Adding secondary glazing with dim-out blinds to windows to reduce thermal gain and shut out light
- Placing UV filters over window glass to minimise damage from ultraviolet light
- Checking plumbing systems regularly to ensure that pipes do not leak
- Covering vents or openable windows with mesh to prevent insects entering
- Placing draft excluders under doors to keep out dirt and insects and to minimise air changes
- Capping chimneys that are no longer used, as these allow water ingress and could also be nesting places for birds or entry points for insects
Not all building maintenance is carried out by museum personnel – some requires specialist building contractors. Conservators, curators and front of house staff liaise with the contractors and oversee their work.
Cleaning and controlling dirt
The ideal situation in a museum is to keep the collections dust free. Dirt and dust is harmful because it reacts with surfaces causing chemical change (such as the corrosion of metals) and can encourage mould growth. If left for a long time it can become cemented to the surface and be difficult to remove. Gritty dirt particles can also scratch delicate surfaces, for example textiles, paintwork or soft metals. Dust can also be disfiguring, obscuring details and concealing evidence. To keep collections clean we:
- Use suitable display cases to protect objects from dust
- Place large mats near doors to trap dirt from shoes
- Clean floors and carpets daily using vacuum cleaning with hepa filters
- Carry out quarterly deep-cleaning programmes to all spaces not cleaned on a daily basis
- Carry out regular cleaning of display cases
- Do conservation-cleaning of large objects not in display cases
- Ensure that objects in storage (not on display) are housed in lidded boxes or cabinets, or placed under appropriate dust-covers
This work is carried out by the conservators, assisted by the museum cleaners, the front-of-house team, volunteers and interns.
Physical protection of the collections
Every time an object is handled, moved, knocked or even brushed against, the risk of physical damage is high. Wrong handling can result in irreversible harm such as scuffing or breakage. A careful approach greatly reduces the risk; at RAMM we:
- Protect displayed collections in vibration-proof, sturdy cases made of laminated glass
- Use barriers to keep visitors at a safe distance (where objects are too large for a case)
- Use museum gloves when touching/holding objects to prevent sweat and sticky dirt on hands from contaminating the objects
- Train staff in correct ways of lifting and moving objects
- Protect stored objects in boxes, drawers or cabinets
- Ensure appropriate packing methods are used when objects are travelling out of the museum
As well as controlling the environment around the collections, we also need to examine objects regularly to see if damage is occurring. The routine checking of the whole or part of the collection is known as a condition survey. At RAMM we aim to carry out condition surveys of the whole collection every 3 – 5 years.
The survey information tells us what objects are at risk from further deterioration and whether the housekeeping measures we are using have been successful. It also helps us plan future conservation work priorities. Different parts of the collection are examined for other reasons, such as for exhibition or loan. Condition checking tasks include:
- Regular inspection of the of the objects on long-term display
- Condition checking of objects going on (or coming off) display
- Examination of all incoming (newly accessioned) objects
- Condition checking of outgoing or returned loan material
- Regular spot checks of collections within the storage areas
When conservators talk about the museum environment, they are referring to specific conditions around each object, such as air temperature and humidity and how much light is shining on it.
Temperature and Humidity
Though museum buildings protect collections from the direct effects of the weather outside, the environment inside is still changing, i.e. becoming hotter when the sun is shining or moister when it is raining. Peoples’ breath and body heat also adds to the problem. The constantly changing temperatures and humidity levels within a museum can be hazardous to many materials.
Everyone is familiar with measuring air temperature in °C or °F. In the museum it is important for us to understand how wet or dry the air is too. High humidity (lots of moisture in the air) causes corrosion of metals, swelling in organic materials (leather, paper, textiles), and encourages moulds and insects to grow and breed. Well known examples of damage in damp conditions are: the rusting of iron, mould growing on walls and the warping of wood. The opposite happens when the air is dry (when humidity levels are low) – organic materials dry out, shrink and crack.
Our aim is to ensure that the museum climate is stable and the best we can achieve for the sensitive materials housed within it. Temperature and humidity levels are measured (monitored) continuously so we know where problems occur. Ways of slowing down changes in temperature and humidity are:
- Keeping the heating turned down in winter
- Keeping windows and doors closed as much as possible
- Maintaining display cases to ensure seals are airtight
- Protecting objects in cardboard boxes and tissue paper in the store rooms
- Fitting filters and blinds to windows to reduce thermal gain
Light damage and control
Most people are familiar with some effects of light damage, such as the fading of cloth and darkening of newspaper. Light is a high energy source which causes chemical reactions to take place in the surfaces of some materials, especially organics, resulting in visible and chemical alterations, such as colour change.
All light, whether from the sun or from indoor lighting, is potentially damaging to collections. Ultra-violet (UV) light is high in energy and causes the most damage, but being invisible is not needed to view objects on exhibition. Therefore all the internal museum lights we use are UV-free.
When objects are on display they have to be lit at safe levels to reduce the effects of light damage. Dyed textiles, watercolours and certain inks are particularly light sensitive and need to be displayed in low light levels. Conservators measure light energy using digital meters so they can check that the light falling on an objects is not too bright. Many light sources, such as spot lights, also give out heat and need to be kept a safe distance from the object.
We can control museum lighting by using low wattage bulbs, dimmer switches or by choosing special types of lights, such as fibre-optic or LED lights. These emit light of lower energy, with reduced heat, so there less risk of damage to objects and they are especially useful when close-up lighting is needed.
Light damage is cumulative (increases over time), so collections not on display are kept in the dark. Light sensitive objects must not be displayed for long periods – they need ‘rest’ periods in the dark to minimise damage. We take active steps to reduce the effects of light:
- Measurement of display lighting to ensure levels are safe
- Keeping window blinds or curtains closed to cut out direct sunlight/daylight and minimise thermal changes.
- Using UV filters over lights; placing UV filtering film on windows, skylights and display glass.
- Using low-energy lights with low UV output, e.g. fibre-optics and LED
- Covering and boxing of objects when not on display
- Having timed lighting which switches on and off, or lights which are sensitive to people approaching and moving away.
- Reducing the duration of the display period
- Covering an object with a curtain which visitors can lift off or draw back.
Museum pests are the living organisms which damage or feed on collections. They include: insects, moulds, rodents and birds. All can be voracious feeders, capable of completely destroying objects in a few weeks. Some species feed only on a particular material, e.g. moths on hair, fur and feathers; furniture beetles on wood, and booklice on starch.
Knowing exactly what pests might be feeding on an object helps us make plans to save them from further damage. Insects are our main target as they move very quickly around the building and being small can hide unseen in dark corners.
To check their movements around the building we use small sticky traps placed at strategic points. Conservators are trained how to identify insects using microscopes. Every species is a different shape with distinctive markings. Through the microscope they appear enormous and we can see more easily the jaw parts, wing shapes, hair patterns and different colours.
We don’t only look for the pest itself but also signs of its activity. Some insects, such as woodworm larvae, can hide away deep inside wooden objects, gnawing away at the core, unseen. Conservators must therefore search for tell-tale signs such as holes in the surface, or piles of dust underneath. Items on open display, such as wooden furniture, are particularly vulnerable and must be checked regularly.
Soft fabrics, e.g. woollen textiles, carpets, and stuffed animals and birds, are also prime targets for insect activity. Moths and carpet beetles feed on hair, fur or feathers. They leave surface evidence, such as bald patches where they have been grazing, cast skins, or larval cases.
When we find activity we isolate the damaged items, wrap them in plastic and freeze them. This is to kill the adult insects, their larvae and eggs. In museums we try to avoid using insecticides and pesticides.
The best way to deal with pests is to prevent them spreading in the first place, so we carry out good housekeeping, routine monitoring and quarantine programmes. This approach is known as pest management.
Pest management begins outdoors where many pests live in adult form but may move indoors to over-winter or breed. Preventing them from entering the building is crucial. There are many ways to control their entry.
- Keeping Museum outdoor areas clean and well managed so as not to attract larger pests, such as rodents and pigeons
- Keeping rubbish bins closed and well away from the museum’s entry points
- Use of pigeon proof equipment, such as nets and anti-roosting spikes
- Clearing away vegetation from building walls, drains and downpipes so they do not harbour insects or become nesting places for birds (insects such as carpet beetle breed in birds’ nests)
- Other building maintenance tasks mentioned under ‘good housekeeping’
Knowing what pests are inside the museum requires regular monitoring which forms part of the overall pest management and housekeeping programme. Keeping them isolated by quarantining incoming material is also an important strategy. Other housekeeping actions involve controlling the indoor environment where the objects are kept, so it does not contribute to their survival.
Effective ways of managing pests involve:
- Ensuring that rooms are clean and uncluttered so pests can’t hide away in dirty crevices or under piles of boxes
- Keeping foodstuffs, houseplants and materials that attract insects away from the collection areas.
- Routine inspection of potential entry or exit points, – such as windowsills, doorways, skirting boards, disused fireplaces, air-vents and loft hatches.
- Strategic positioning sticky blunder traps to determine where insects move around the building and where they might be breeding
- Regular checking of traps to do population counts
- Identifying the ‘catches’ to know which insects are being caught and whether they are harmful to museum collections.
- Training of front-of-house and cleaning staff to look for the telltale signs of pest activity (e.g. wood dust under furniture) and on what to do if they suspect anything.
- Blocking or meshing of entry points, such as vents, openable windows, and fireplaces
- Developing a quarantine procedure which involves the inspection of incoming material or material which has been on loan or returning from another site.
- Routine freezing of objects, where pest activity is suspected, to kill the pest infestations.
- Keeping temperatures in the store rooms cool (around 15-18ºC) to slow down the breeding cycle of insects
- Keeping the humidity levels below 65% to retard mould growth