People may think of silver as strong, but it bruises easily, gets dirty and reacts with the air. The features that make it so attractive, its softness and lustre, are also its weaknesses.
Silver blackens in the air. It reacts and combines with different substances in our environment to form compounds called tarnish.
Industrial air pollution and fumes from vehicles are major contributors. However, materials closer to home can also be hazardous; wood, wool, leather, textiles, rubber bands, newspaper, adhesives and even vegetables and egg all emit sulphurous and acidic gases. This is why egg spoons and salt cellars are often gilded. Research has also proved that baize, for many years the standard lining for cutlery drawers, actually releases sulphur - accelerating tarnish. People can also harm silver. Handling it with bare hands deposits potentially damaging salts and oils which in time eat into, or 'etch', the surface. Silver, like most metals, tarnishes faster when it is damp. The Museum strives to maintain stable levels of humidity and temperature.
Every time silver is cleaned a small part of the metal is always removed. In time, the surface wears away and details such as engraving and hallmarks may be lost. If the object is plated, the thin silver surface disappears exposing the metal beneath.
Our aim is to arrest the effect of time enabling the visitors, present and future, to understand and enjoy the objects. Objects should be structurally and chemically stable. If they are not free of tarnish and dirt they continue to deteriorate. All treatment is documented and reversible. We begin by examining each object closely to assess its needs. It is important to understand the techniques that were used to make the object. Sometimes, surfaces are deliberately coloured or 'patinated'. This finish must be preserved. Silver objects may incorporate other materials: ivory, textiles, enamels or other metals. Any treatment must be safe for these materials too.
Cleaning and surface treatment of silver
To remove dirt, grease and old lacquer we use solvents on cotton wool swabs. To remove tarnish we apply a chemical cleaning solution with cotton wool and rinse it off with de-ionised water. Alternatively, a fine polishing paste or an impregnated cloth may be used. Used carefully these treatments can improve the appearance of silver objects, while retaining signs of wear, which are evidence of past use.
Once the object is clean and grease free, we brush on a colourless lacquer to protect the surface. As long as clean gloves are worn when handling the object, this lacquer can last up to ten years or more, cutting out the need for frequent re-cleaning.
Fractures or dents may weaken the object, which might then require strengthening. If old repairs are weak or unsightly they may be replaced. We re-attach broken parts using reversible adhesives or occasionally by soldering. Where we have to replace a missing part, we strive to match the original materials. And each part is clearly marked 'V&A' with the year of manufacture.
There are more than 12,000 silver objects in the Museum collections. Conservators and curators monitor their condition regularly. We conduct condition surveys to increase our knowledge of the state of all the objects, those in storage as well as those on display.
Objects from the V&A are often sent on loan to other museums and galleries around the world. They are at their most vulnerable when in transit. Skilful packing, using tailor-made cases protects objects from damage by shock and rapid changes in environmental conditions.
Action behind the scenes at the V&A
Research and preventive conservation are always in progress. They are a vital part of protecting the Museum's collections. A major Museum project, such as the re-display of the Silver galleries, is an opportunity to investigate and improve the conditions in which objects are kept, collaborating with other institutions.
Through research we are constantly looking for new and better techniques to protect the Silver collection from corrosion and wear.
Conservators and scientists from the V&A and other institutions are pooling ideas, information and resources towards finding a long-term method of reducing pollutant levels in cases. If levels can be reduced to stop corrosion, the method could be developed for use throughout the Museum.
Coupons of unprotected silver are 'test samples' that let us know the exact conditions that the objects are exposed to in cases and storage cupboards. They can be analysed to investigate the types of corrosion that have formed.
Diffusion tubes provided by Brookes University, Oxford, monitor the levels of pollutants in old storage cupboards as well as new showcases to build up a picture of the invisible environment inside the cases.
Adsorbent materials pioneered by the British Museum, are on trial to see if they can reduce pollutant levels inside the cases. Adsorbent materials trap pollutants, lowering the pollution levels. Examples include zinc oxide granules and activated charcoal cloth.
The display cases are the first line of defence - air-tight with a stable temperature. They are monitored to assess their ability to maintain a favourable environment.
The Museum uses many unseen methods to minimise risk and avoid damage to museum objects.
Materials used in the cases are tested to exclude products that emit harmful substances.
Protective coatings on the surface of the objects form a protective barrier to prevent tarnishing.
Salvage and fire fighting equipment as well as trained staff are available in the event of a disaster.
Insect traps form part of a programme to monitor and combat pests which damage organic material.
The galleries are cleaned regularly to keep harmful dust to a minimum.
Blinds provide extra protection from the sun's heat.
Fibre-optic lights provide light without raising the temperature.
Specially made mounts support and hold objects safely.
Cases and windows have tight seals to combat pollution, dust and dirt.
Transparent films coat the windows to filter out the damaging ultraviolet light and also to prevent the sun's energy from raising the temperature too high.
Trays are fitted in the cases so we can introduce absorbents which reduce pollution, or silica gel to control the humidity.
Probes that measure temperature and humidity in the case can be inserted without disturbing the display.
Security guards keep a watchful eye in the galleries, and the cases are reinforced to prevent theft.
A central computer monitors the fluctuations in temperature and humidity in the gallery and the showcases.