How To Look After Your Paintings
The first thing a collector can do to ensure that the paintings in his or her care are in a good condition, is to examine them periodically and carefully. This is to ensure early detection of any deterioration which may require treatment. The following questions should be in mind:
Is the canvas…
- buckling at the corners or very slack?
- torn or split?
- turned a very dark colour?
- brittle and splitting at the tacking edge?
- showing the stretcher from the front?
- showing mottled staining or mould spores? (If so isolate the painting and reduce RH.)
Is the stretcher…
- warped? (If so, regulate RH.)
- showing signs of woodworm? Look for fresh sawdust and worm holes where the wood has not yet darkened in the hole. (If this is found, isolate the painting.)
- missing wedges? (Wedges can be fixed in place so that they do not fall out by using a bit of gummed paper holding the wedge to the stretcher. Missing wedges should be replaced. Ask a conservator to show how.)
- Have wedges or other objects become stuck between the canvas and the stretcher? (This will be easily felt from the front by very lightly running fingers along the bottom edge of the painting)
Is the panel…
- warped or twisted and does the warp appear to increase according to different levels of humidity?
- showing signs of fresh woodworm infestation, light coloured flight holes, worm channels, caved in paint on surface following grain? (If found isolate painting.)
- showing signs of mould, has the panel changed colour, becoming redder, does it show mould spores, or dry rot? (If so isolate the painting.)
Is the ground and paint layer…
- flaking? Check this with raking light, a torch (flashlight) held so that the light falls along the surface should show this up. (If this is found lay the painting flat in a place away from draughts.)
- cupping badly, showing pronounced raised edges? (Check and treat as above.)
- losing flakes of paint? (Check and treat as above.)
- blanching or blooming? (If so reduce RH.)
- obviously fading? (If so eliminate ultra violet and reduce light levels generally.)
- obviously dirty? (This is particularly serious on an unvarnished painting.)
Is the surface…
- cloudy or opaque?
- badly discoloured?
Is the frame…
- splitting at the joints? (If so remove the painting from the frame.)
- warped? (Remove the painting from the frame.)
- showing signs of woodworm or mould? (Remove the painting from the frame.)
- flaking or losing pieces of moulding? (Lay flat away from draughts.)
Are the hanging arrangements…
- strong enough to hold the painting?
- is any wire or cord frayed? (If so, replace it.)
- are chains stretching? (Replace with heavier chain.)
- are plates, brackets screws etc. well attached?
If the answer to any of these questions is yes then it would be prudent to consult a conservator.
Environmental conditions may be the cause of any of this.
A backboard (possibly made of hardboard) could be attached behind the frame to reduce some of these effects by greatly reducing the fluctuations in temperature and relative humidity.
The collector should also ensure that hanging, transport and storage of paintings follows conservation guidelines.
Paintings being transported by road, air and rail are vulnerable to different sorts of stresses. If a vulnerable painting is being moved it is important that the collector uses a firm which specialises in shipping and handling fine art. Both dealers and conservators can advise on this.
A few helpful rules on the handling of paintings:
- Never hold a painting with fingers tucked into the stretcher, pressing against the canvas. Do not lift the painting by the stretcher bar if this may be loose.
- Never touch the surface of an unvarnished painting or the gilding of a frame with dirty or sweaty fingers.
- Plan the route and ensure that there is a padded place for the painting to be set down. Ensure that the padding is thick enough to accommodate ornate frames.
- Never hold frames by elaborate mouldings or carvings. Lift from the back outer edges and from underneath.
- Check that the painting is well fixed in the frame.
Hanging paintings generally follows conventional practice, but do note that:
- Chains of the correct weight hung from picture rails provide a greater flexibility for adjustment.
- Heavy paintings are more secure if the weight is also supported by a bracket below.
- Avoid hanging over a fireplace or a radiator or in front of a hot flue.
- Avoid hanging over air conditioning ducts.
- Avoid hanging in direct sunlight.
- Avoid cold outer walls where there may be a danger of condensation.
- Avoid other damp places such as food serving areas, kitchens and bathrooms.
- Hang above the level where people and furniture can be pushed into the painting.
In storing paintings many people forget to apply the same rules as they would for a painting which is hung. The environment in which it is stored is just as important and extremes should be avoided. Basements and attics are not usually good places as they are either excessively dry or damp (or fluctuate wildly) and often lack ventilation. Consider carefully insulating an attic if it is to be used. The guidelines on the environment given below of course also apply in storage.
- paintings which are to be stacked should have all fixings removed.
- Never stack framed and unframed paintings together. Unframed paintings should be stacked face to face and back to back.
- Keep stacks of paintings to a minimum size, placing a weight on the ground in front of stack to stop it slipping.
- Put the largest painting at the back always ensuring that there is never anything protruding into the painting itself.
- Use pads to protect the base and corners of paintings and to separate paintings.
- Consider having a picture rack built if there are too many paintings. This could be in the form of a vertical rack or pigeon hole system.
Finally the collector should consider the environment in which the painting is kept.
Paintings have only finite light life allotted to them. The effect of light is cumulative so the longer they spend in the light or the brighter that light is, the shorter their life. This applies particularly to watercolours but is also true of oil paintings although these have a greater tolerance. The brightness of the light and the length of exposure should therefore be balanced but a general rule of thumb is that paintings should be kept in light at less than 200 lux or (20 footcandles). The limit for watercolours is 50 lux. This can be measured using an ordinary lux meter and should be part of any report made by a conservator on the preventative conservation of a particular painting in its setting. Ideally you should keep paintings, or furniture and textiles for that matter, in the dark when there is no one there to enjoy them. This is easily achieved with blinds, shutters or curtains. If this is done a bright light for short periods is perfectly acceptable. Light levels for viewing paintings can be very much lower if you help the eye by reducing the contrast between the wall and the painting itself. A dark painting on a dark wall allows the eye to adjust to the light level required to see the painting far more easily.
Ultra-violet light is very destructive and should be totally eliminated wherever possible. This can be achieved using UV filters on windows, the light source itself or the glazing (glass) on the painting. Such filters are manufactured in the form of a adhesive film which can be applied over window glass and which is then quite invisible. A conservator should be able to advise on how to obtain such filters. Simply bouncing the light off a wall which has a high tinting white pigment will absorb much of the ultra-violet in the light. This can also help in reducing the level. It is helpful to note that ordinary (incandescent) bulbs have virtually no UV whereas tungsten halogen and fluorescent bulbs do. The equipment for measuring UV is expensive so I advise consulting a conservator if you have any worries.
Heat speeds up the chemical reactions which cause paintings to degrade and changes in temperature affect the relative humidity and thus the expansion and contraction of the painting. Paintings should be generally kept at about 18-22Â° Celsius (65-75Â° F). Note that the lights used to illuminate paintings can give off considerable heat. Traditional picture lights will greatly heat up a painting. This heat will be uneven and periodic as the lights will not always be on. This will badly affect the expansion and contraction of the painting. Similarly direct sunlight should be avoided on sensitive paintings. The UV films can also incorporate an infra-red filter to reduce the solar gain. This of course is less energy efficient when considering household heating systems (but not air conditioning) so a balance needs to be considered.
I will not here explain the principles behind relative humidity, suffice it to say that the relative humidity in the air will affect the moisture content in the painting and thus affect its expansion and contraction. Fluctuations in relative humidity (RH) are therefore to be avoided. The generally acceptable range for keeping a painting is between about 40% to 70%. As has been stated earlier this range is far smaller for museums and should also be smaller for sensitive panel paintings (55% ± 5%) In order to know what are the RH conditions around a particular painting it is necessary to measure this over time and ideally over several seasons. The equipment for this, a thermohygrograph (hygrothermograph in the US), is not reliable if not calibrated frequently. Cheap digital thermoyhgrographs are usually unreliable and it may therefore be prudent to consult a conservator if you have any worries. If it is found that the humidity is not within acceptable levels or fluctuates greatly a conservator should be able to advise on ways of modifying the environment. Dehumidifiers and humidifiers can be a solution but they generally require constant maintenance and are quite expensive.
Finding a good conservator is not always easy. The collector should choose a conservator who has had a good training and is a member of his professional body. Check the insurance and security arrangements. The conservator should give a clear assessment of what he intends to do and then keep the owner up to date with any developments. Conservation is extremely labour intensive work and as such can take some time. The collector should understand this. There should be a clear report of the treatment along with a description of materials used at the end. It is the duty of the owner to keep such a report with the work of art. A good picture dealer is well placed to advise on finding a good restorer.
Dealers are arguably the best judges of the quality of a painting conservator’s abilities; better than many auctioneers and curators.