Five years in the auction industry has given Oswald an insight into most of the issues that come up in running an auction house. Oswald is probably the person you are most likely to talk to if you call the office.
With this guide to caring for antiques, you can ensure they will last for many more years to come.
It’s remarkably easy to cause damage to antiques and collectables, but the good news is it is also relatively easy to avoid once you know how to prevent it. Here are some tips.
Thankfully, you don’t need to turn any rooms into a museum to preserve fragile and precious objects. Mostly it’s common sense. Location is the most important consideration when caring for antiques: light, temperature, pollution are just some of the factors that can wildly affect an object.
Organic materials such as paper, leather and wood are more sensitive to their environment than stone, ceramics, metals and glass. Objects made from a variety of different materials need to be treated with the most vulnerable material in mind. This way you can limit any possible damage effectively.
It fades colours, breaks down fibres and alters the chemical make-up of objects.
The most harmful component in the light is the ultraviolet (UV) wavelengths. UV-free lights and UV filters for fluorescent tubes are an option. Other barriers against ultra-violet such as self-adhesive film or spray-on varnish can be applied to unleaded windows, but not to stained glass or any prone to condensation.
Long exposure to weak light can also damage as much as strong light for a short period. Make sure to keep any vulnerable items away from strong or direct sunlight. Blinds and net curtains have a filtering effect which helps to mitigate the light’s effects. Infrared rays from ordinary, incandescent bulbs radiate dehydrating heat, which is harmful if allowed to spotlight on a work of art or build up in the enclosed space of a display cabinet.
It may be better to light a display from outside the cabinet rather than within it. Fibre-optic lamps with adjustable levels of light and cool beams are available, but they are quite expensive.
Temperature and Humidity
Temperature and humidity can cause materials to expand or contract. Organic materials absorb moisture in a damp environment and expand.
They release moisture in a dry atmosphere and contract. Both lead to wood warping, splitting and cracking. In a damp atmosphere, tarnishing and corrosion of metals is more rapid.
The ideal ‘museum’ level of relative humidity for antiques is around 55%, which is a perfectly acceptable level for living in, although a centrally heated home may be on the dry side at 40-45%.
You can check humidity levels with humidity indicator cards or strips with a simple hygrometer, available readily on the internet or in garden centres. Humidifying and dehumidifying devices range from simple gadgets which clip onto radiators to expensive, freestanding electric models.
Be cautious not to combine heat with over 60-65% humidity, as those are ideal conditions for mold spores and wood warping.
An atmosphere that fluctuates between extremes of temperature and humidity is the most damaging of all. For example, a piece of furniture that has been in a cold damp house for generations has adjusted to its environment. If it were suddenly moved to a warm centrally heated room, it would warp and crack. Veneered surfaces might peel away from the carcass.
So it’s best to aim for as constant a temperature as possible. Keep rooms well-aired and vulnerable items away from condensation, steam, direct heat from radiators or lights, or chilly walls against the outside of the house.
Car exhaust fumes, factory emissions and burning fossil fuels all produce greasy films of fine dust and harmful gases.
They combine with moisture to form acids in the atmosphere. These can slowly eat away at vulnerable materials such as textiles. Destructive substances within the house include acetic acid in in vinegar and vapours from freshly painted rooms.
Some composite woods like chipboard give off Formaldehyde which acts as a corrosive. It can also cause destructive reactions in other materials.
Air conditioning and glass or Perspex-fronted display cabinets provide protection but are not usually necessary. General awareness of the problems will be fine: ventilate rooms well if they have been filled with smoke from open fires or candles. If you live in a town or city, keep sensitive and unprotected articles away from open windows.
Vermin and Insects
Rats, mice, woodworm, beetles, moths, silverfish, thrips and thunderflies are some of the pests that might become problems. Commercial insecticides and pest repellents may be effective but may also damage the piece you are trying to protect.
Preventative measures are the best defence. Inspect your pieces regularly – every year for books and textiles, twice a year for furniture – so that a problem is identified before too much damage can be done.
If any pieces are infested, isolate them and seek expert advice.
Few of us can afford to take every damaged object to a conservation expert. But with antiques, never leap recklessly into home repair; you could damage a piece irretrievably and destroy its value.
A home repair is unlikely to be the ‘invisible mend’ a specialist could achieve, and you may find that your handiwork needs to be undone, in a far more expensive professional repair later.
If you do make a temporary repair, the most important thing to do is make sure your repair is reversible (by using water-soluble glue, for example). Be certain before you begin of the type of material you are dealing with, and its vulnerabilities.
Some antiques are worth more unrepaired than repaired, even if it’s done by a professional.
If in doubt, consult the conservation department of a major auction house or museum before any repair or major restoration. Take a clear photograph of any valuable object when you first acquire it; if it is subsequently broken, this could be a useful reference for the conservator.
A starting point for finding a reliable restorer is a recommendation from an auction house, trusted dealer or museum. Other useful sources include: The Museums and Galleries Commission, the United Kingdom Institute for Conservation, and conservation training institutions such as the Courtauld.
Look for a specialist conservator or a large workshop that employs specialists. Ask what materials and methods are going to be used for the job – if it is suggested that a veneer is to be glued with epoxy resin rather than reversible animal glue, find another conservator.
The cost of restoration depends mainly on how long the repair will take, plus cost of materials and VAT. It bears no relation to the value of a piece; as a paper conservator once commented, ‘whether a print is worth £20 or £10,000, we treat it in the same way and charge the same rate’.
Get a written estimate of the cost and completion date. Check whether delivery is included in the price. When the piece is handed over to the conservator, get a receipt and check who is responsible for insurance during restoration. On completion, ask for the details of restoration to be included on the receipt. Keep this as a record.
To withstand daily wear and tear, there are some things you can do to limit any damage.
Be mindful of your antique furniture’s original purpose – and its potential shortcomings in modern life – for example, the surface of an old desk was not designed to withstand the pressure of a ballpoint pen, and you may find your writing etched onto the surface if you don’t put something behind the paper to lean on.
Tilting back on a chair, opening a drawer by only one of the handles, dragging furniture rather than lifting it, all put unnecessary strain on the structure.
Before lifting furniture, empty any contents and remove detachable parts for carrying separately. Take hold of the lower part of the main frame – not, for example, the top surface of a table – and pick up chairs under the seat.
A surface patina (even marked and/or damaged) contributes to the character, authenticity and ultimate value of a piece of furniture. If restoration is necessary, the original finish should be matched at closely as possible. French polishing or the tough synthetic varnishes of the 20th century should not be used to replace wax or shellac, for example.
Oil or beeswax polishes are the most common finishes on 16th and 17th century furniture, and on oak and country furniture to the 19th century. They are also more resistant to minor bruises and spills than varnish or lacquer.
Resin and shellac varnishes were originally used on fine furniture from the end of the 17th century onwards. Like lacquered and japanned finishes, these are spirit-based and can be marked by other solvents such as alcohol, as well as by heat, damp and abrasives.
French polishing, introduced in the early 1820s, is a method of applying shellac that achieves a high-gloss finish with less effort. It is also less durable and prone to chip. Newly applied French polish is particularly vulnerable. It can take up to six months to harden completely.
Other finishes include graining and ebonising, where a surface is stained to resemble an exotic wood. This effect will wear away with too much rubbing.
Veneered furniture is particularly vulnerable to dry or damp conditions. If water polish seeps beneath the surface skin, it can cause the veneer to buckle, lift or split. Inlaid finishes such as marquetry and boulle are even more sensitive; the materials react to heat and humidity at different rates, resulting in uneven stress over the surface.
Dusting and Cleaning
Frequent dusting is important, especially on a waxed surface which is soft and absorbs dust and dirt.
Try to dust before cleaning or polishing as particles of dust are abrasive. Use a clean dry duster with no frayed edges (which could catch) for most jobs, but for any surface that has begun to lift or crack, use a soft bristled brush (also handy for crevices). Check that no grit is lodged in the brush and cover sharp edges with masking tape. Feather dusters are not ideal as the feathers break and the spines could scratch a delicate surface.
Spot-test any inconspicuous part of a piece of furniture before trying to clean it. No fluids should be used to clean porous materials such as mother of pearl or ivory, or damaged lacquered, painted or veneered surfaces.
A sound waxed or lacquer surface can be cleaned with a soft damp cloth (add a tablespoonful of non-ionic detergent to a washing-up bowl of warm water). Wipe the surface with a clean cloth rinsed and wrung out in clear water and dry immediately with absorbent paper. Never use detergent on unpolished or damaged wood surfaces, as it could penetrate and stain.
If spillages are dealt with immediately, they are unlikely to harm a sound wax or lacquered surface. Candlewax may lift off easily in a slab when cold. If that fails, it can be warmed with a hot-water bottle wrapped in a clean cloth and then scraped off with a fingernail or orange stick.
Deeply ingrained stains should be left for an expert to deal with, or left to contribute to the character of the piece. You can try treating the whitish marks left by the damp base of a glass, for example, by wiping with a little metal polish, if the surface finish is not delicate and if it is wiped clean with a damp cloth and dried immediately.
All sealed wooden surfaces can be waxed to bring out the colour and grain of the wood and to provide protection against staining. Over-waxing will cause dullness. Furniture that has been waxed and polished over the years should only need buffing with a soft chamois leather or duster, and a waxing maybe once every few months.
Some solvents used in furniture polishes – especially the spray-on types – may leave a whitist bloom on some surfaces or gradually dissolve lacquered finishes. They should not be used on any lacquered surface and only sparingly on wax.
A microcrystalline wax is the best medium for giving protective and burnishable coating to most surfaces, including ebonised wood, lacquer and French polish. Apply the wax over an area about 1ft (30cm) square at a time, burnishing with a soft clean cloth as it dries. Use a soft-bristled brush for carved surfaces, leaving no surplus polish in the crevices.
Brass mounts don’t have to be ultra-bright on antique furniture; light burnishing as you dust should be fine, or buff with a long-term silver cloth. Metal cleaners should not be used as they can harm the wood around them.
The gold finish on ormolu is very delicate and should never be polished. Even fingerprints can damage gildings. In time the brass or bronze base corrodes, giving the finish a spotty and then black appearance. The mounts can be lacquered (see metalware) but even this will fail in time. Other than dusting ormolu gently and regularly with a soft brush there is little else to do; never have it re-gilded if you want to retain the value.
Caring for Gilded Surfaces
Water-based gilding remains water soluble and should only ever be dusted, whereas oil gilding may be cleaned by gently dabbing with barely moistened cotton wool.
Water gilding is applied over layers of gesso, and may be burnished to a high shine, although some areas may be left matte. Oil gilding is sometimes applied directly into wood and has a matte finish. Chips in a gilded surface can be filled with a fine surface filler and disguised with yellow ochre watercolour paint.
Avoid using ‘gold’ metallic paint for areas of any size, as it clashes with the true gilding. A professional gilder’s aim is to match the original techniques and materials, and to retain as much of the original surface and patina as possible.
Dealing with Woodworm
Adult furniture and pinhole beetles lay eggs in crevices in wood. The eggs hatch into larvae (woodworm) which eat into the wood, leaving tunnels some 1mm in diameter, before they emerge as beetles and fly away, usually between May and August. Active infestation is revealed by freshly bored holes and deposits of sawdust or ‘frass’.
Check – and treat – any new purchase before you take it into your house. Check all wooden objects twice a year for infestation – especially bare and softwood surfaces such as the insides of drawers and backboards. Upholstered or particularly delicate furniture should be professionally fumigated. On other items a good quality, clear low-odour woodworm fluid can be applied at home.
The best time for treatment is late spring or early summer. Remove any detachable upholstered parts and only treat the unfinished surfaces, or the wood-solvent in the fluid will damage waxed, polished, varnished, lacquered or painted surfaces.
Carefully paint on the insecticide. Injecting insecticide, using a hypodermic syringe and needle to reach deep into the holes, should be left to an expert. Following treatment, fill the holes with soft wax to blend in with the surrounding wood.
Unlike many other antiques that devalue due to restoration, furniture that has been restored using traditional methods and materials can be worth more than a damaged item. If you do make minor repairs yourself, only use water-soluble wood glue.
Almost all furniture made before the mid-20th century depends on well-jointed solid timber for strength. Weaknesses in joints, pivots, moving parts, on load-bearing surfaces, or signs of rot or woodworm must be fixed before the piece is used again.
A restorer can reinforce or replace damaged timber with sound wood, saturate it with resin or fill it with a mixture of animal glue and sawdust. Sticking doors or drawers may fixed with a touch of candle wax. If they are misshapen they need to be trimmed by an expert. Chipped or lifted veneer should be professionally repaired as soon as possible, but exposed edges can be temporarily protected with masking tape and detached pieces kept in a plastic bag.
If stripping is necessary and will not remove a valuable patina, it should be done by a furniture conservator. Acid stripping swells and rots wood fibres.
Dry cracked leather on desk-tops (and bookbinding) can be revitalised with a lanolin and beeswax preparation such as Connolly’s Hide Food. Spot-test the dressing on an inconspicuous area; if it leaves no stain, then apply it sparingly with a soft cloth. Let the dressing absorb (about 24 hours) before gently buffing with a clean duster.
Upholstered furniture must be vacuumed regularly to guard against a build-up of dust and pests. If necessary, you can use a net of fine-meshed tights over the nozzle to prevent any loose pieces being damaged.
Fine old upholstery fabric should be reserved for display only. A loose cover can offer some protection. On some seat furniture, upholstery can be re-webbed or re-stuffed, or the fabric replaced with a sympathetic alternative, without detracting from the value of the piece.
Seek expert advice first. Make sure that newly re-upholstered drop-in seats are returned to the correct chair. Any new coverings shouldn’t be so tightly fitting that it strains the leg joints.
With thanks to Readers Digest.