Care & Conservation of Paper Artworks

Art collectors all over the world are confronted with two major challenges. One is the management of various formats of artwork coming to their collection, and the other is to preserve them for posterity. In order to handle them professionally, Conservators are well aware of the magnitude of the problems they are going to tackle and well acquainted with the aesthetics and practices so that their functions can be discharged in a scientific manner.Throughout the history of art, technological advances have influenced both the materials and the methods used to create works of art on paper. While there is no doubt that twentieth century artworks have unique conservation problems, drawings done with unorthodox media or using nontraditional techniques need not be banned from collections because they require stringent lighting and exhibition restrictions, among other conservation constraints.Works of art on paper should be touched as little as possible. Paper could be damaged by prolonged exposure to the acidic surroundings, the choice of storage and mounting materials is crucial. Mats, folders, and mounting adhesives must be chemically stable, non-staining, and permanent but reversible. It is important to use preservation-quality framing materials for safe-keeping your collections. A paper conservator or a major museum manager can offer you with the relevant requirements.

Natural calamities like earthquake, flood, fire; man made actions like war, atmospheric pollutions caused by industries, extreme climatic conditions; biological infestation, the quality of material used for recording etc. contribute to the destruction of paper artworks. The five most critical and inter-related factors in climatic conditions are the fluctuations in temperature, relative humidity, atmospheric pollutants, lighting and micro-organism.

Regular changes in temperature and relative humidity create stress on paper, weakening paper fibers, and cause them to loose cohesiveness.If an artwork could be maintained in an optimum environment, with constant temperature and humidity levels, many of the problems requiring the services of a conservator could be prevented. Artworks do well in conditions with relative humidity (RH) levels at 50-60 %. High temperature and RH encourage mould growth and insect activity. Very low RH, below 25%, is believed to be less damaging but may cause paper to become brittle. Gradual seasonal changes and small fluctuations are less harmful.For example, a paper artwork stored in poor conditions may remain stable for centuries, but begin to deteriorate rapidly if exposed to extreme change. One of the simplest preservation steps is to assemble a protective non-acidic backing board (non-wood base) to paper artworks. Ensure that this covers the entire back of the framed artwork, to keep artwork from exposing directly to the environment.

Gaseous pollutants such as sulphur dioxide, hydrogen sulphide and nitrogen dioxide hasten the degradation of all materials. Ozone, another atmospheric pollutant also causes oxidation and paper brittleness. Ozone gas is present in the air after thunderstorms. It also forms from the interaction of sunlight and nitrogen dioxide in automobile exhaust. In addition, dirt, dust, soot, tar and other solid particles suspended in air carry absorbed pollutants can damage paper artworks through abrasive action. It should as much as possible be dust and pollution-free via air-filtration system.

All organic materials like paper, pigment and photographic materials are susceptible to deterioration through exposure to light. Light has two damaging effects on paper: bleaching action cause whitening of paper and the facing of coloured papers and certain inks; and also causes lignin to react with other compounds. Ultra-violet rays in sunlight and fluorescent lighting promote oxidation of cellulose fibers and can cause paper destruction. Avoid direct sunlight and bright lights (such as fluorescent lamp) as this will encourage rapid degradation. . It is ideal to install UV-filter lightings for such materials. Quality of photographs and blueprints are particularly sensitive to light. Hence, it is important to remember to turn off the lights when they are not needed.

Paper can contain cellulose, proteins and carbohydrates. These elements come from the use of gelatin sizing, glue, paste, leather and other organic substances. Such substances are all attractive to insects and rodents. This knowledge is important because it will dictate the conservation treatments needed, and the best products to accomplish the conservation work. In general, our warm and humid tropical climate is more likely to attract these unwanted agents. Although regulating the temperature and relative humidity can control many problems, good housekeeping practices also help to keep them away:
- Prohibit smoking, eating and drinking in or near the storage/display area;
- Keep storage/display areas free of debris (dusting and vacuuming method regularly);
- Prohibit plants in areas where collections are stored and displayed;
- Seal openings in building to inhibit passage because pests infiltrate through cracks and holes in building structure;
- Engage a professional Pest Control company to disinfect the storage areas and to advise on placing ‘sticky’ traps and Rodent beads around the storage/display areas.

Mould or Mildew is a term generally used to designate a variety of vegetable organism among fungi. The occurrence of mould or mildew in books & volumes is common in hot and humid climate. It can infect even if temperature and relative humidity (R.H.) are controlled. Mould spores are suspended always in the atmosphere. Spores can begin to grow when the temp. is above 80 F(27 c) and R.H. is above 70%. Stagnant air due to improper circulation would promote the growth of mould further. Mould digests the paper material resulting staining (brownish or greenish black patches) and rapid loss in paper strength (FOXING) Mould prevention requires that temp.& R.H. are within protective range. During periods of high humidity, use fans to circulate air and help discourage mould growth. Above all, do not store works of art in basements or attics. Do not hang them in bathrooms or over heat sources. Unless the building has excellent climate controls, do not subject art on paper to seaside locations or other damp areas.

For a paper to be considered acid-neutral or acid free, it must have a pH of 7.0 to 8.5. However, most papers manufactured from the 1850s to the present have a high acid content with a pH factor below pH 4. Therefore, most of them appear to have shorter life-span. The factor contributing to the low PH is due to chemical element found in its sizing agent or unpurified wood fibers during manufacturing. An aluminum compound known as alum-rosin used as sizing agent in paper manufacture though produces a better writing and printing surface, but its acidic by product decreases the life of paper. Another cause of paper deterioration is the use of unpurified wood fibers with lignin content in its manufacture. Ground wood is weaker than fibers of purified wood pulp. 100% rag paper or cotton fiber paper has a higher molecular weight and has a longer life than virgin fiber or pure wood fiber paper. The common effect of lignin is the yellowing of paper (like newsprint paper) when exposed to long duration of any form of lights. Paper manufactured using pure cotton plant cellulose and processed with an alkaline sizing process has a maximum life expectancy of 500 yrs. This has been proven by accelerated aging testing.

In the early days before 1980, poor-quality mounting materials may have been used in framing artworks. An inferior-quality mat board turn browning is one of the common symptoms. Therefore, the following should be considered when framing artwork is required:
- A mat window and backboard made of 100% ragboard or the lignin-free, alkaline-buffered matboard especially for preservation purposes
- Attachment of the artwork to the mat or mount by hinging with high-quality Japanese paper and a permanent, non-staining, reversible adhesive. Homemade starch paste is the choice of conservators. Avoid commercial tapes, including those advertised as archival. If you want to try to do your own matting, a paper conservator can advise you about sources of supplies.
- Protective glazing, either glass or rigid acrylic. The artwork must not be in direct contact with the glazing material. Ultraviolet filtering products, available in glass as well as plastic, are recommended to protect against the most destructive component of light. Note that acrylics carry a static charge and must not be used with pastels, charcoal, or other powdery or flaking medium.
- An additional protective layer of sturdy, lignin-free cardboard at the back of the frame. The frame should also be well sealed to discourage entry of air.

However, unframed artworks on paper need more protection. Artworks must have individual protective enclosures. Although matting is preferred, sturdy individual folders are an acceptable alternative. Similar to matboard, these folders must be made of lignin-free, buffered stock that is rigid enough to provide adequate support. To protect the edges of the artwork, folders should be somewhat larger than their contents. Objects in folders or mats should be stored flat in lignin-free boxes such as heavy-walled Solander boxes, the traditional choice of museums. Oversized artworks are best kept in the drawers of flat files (map cases). These flat files should be made of metal rather than wood since wood gives off acidic gases. Wood files can be used if the interior of the drawers is sealed with a water-based polyurethane coating and lined with a suitable barrier material such as lignin-free board or 5-mil polyester film (Mylar). If you purchase storage drawer units, anodized aluminum or powder-coated steel are recommended.

Works of art on paper are fragile and is easily damaged by prolonged contact with acidic surroundings – even paper in good condition – so support it throughout use and handling. Make sure hands are clean and gloves should be worn for added protection. Cotton gloves are often recommended, but they are not always appropriate because they can make it harder to pick up individual pieces of paper. Clean, close-fitting surgical gloves are good alternative to cotton gloves. Always place artwork on rigid support when picking up to examine closely or carry over a distance. Holding a sheet of paper in hand may cause it to curl and increase the risk of damage. For extra protection, carry loose pieces of paper artworks in folders or mylar enclosures.

Good consideration in displaying paper artworks can prevent physical damage and help to slow chemical deterioration. This increases the life of paper artworks. The effects are not always immediately or dramatically obvious. Paper changes gradually over time; but once changes have occurred they are irreversible or involve complex treatment. The following should be monitored:
- Controlled temperature and relative humidity as mentioned in the earlier part;
- Controlled light to the minimum necessary for the activity. Ideally, paper should be stored in the dark. Light levels in display areas should be as low as possible, and display periods should be limited in terms of duration and or rotational basis. The recommended lighting level is 50 lux or less and should be filtered for UV radiation. Avoid using heat-producing lights and spotlights;
- Areas should be kept clean and well-ventilated. Dust and other pollutants should be kept to a minimum;
- Steps should be taken to protect paper artworks against insect and mould infestation;
- Good housekeeping procedures should be enforced with regular monitoring of storage and display areas.

After examining paintings for loose or flaking paint or mould, dust them every four to six months. Use soft, white-bristle Japanese brushes, sable (such as a typical makeup brush), or badger-hair brushes (called “blenders”). Never try to clean a painting yourself. Commercial preparations can cause irreparable damage to artworks. Avoid using pesticides, air fresheners, or furniture sprays near artworks. Remove artworks from a room before painting, plastering, or steam cleaning carpets. Return artworks only when the walls and floors are dry.Dust and soot will soil paper surfaces and are difficult to remove. Pollutants from industrial gases, auto emissions, and heating compounds are readily absorbed into paper, where they form harmful chemicals. In addition, sources of internal air pollution, such as copying machines, new construction materials, paint fumes, new carpets and janitorial supplies can attack paper. Controlling air quality is difficult. Probably the most practical way to protect artworks on paper is to enclose each object in protective housing made with appropriate materials.

Although hurricanes and earthquakes may be rare in our tropical climate, water accidents such as water sprinklers, are common. Even a small amount of water from a leaky roof, pipes or even air-conditioner can do significant damages to paper artworks. If artworks get wet, call a paper conservator immediately to address the problem. It is important to dry paper right away before mould sets in. Wet paper artworks in frames with glazing must be removed from their frames. If you are hesitate to handle the damp paper artwork, expose the artwork by removing the backing from the frame. If the paper artwork is too large to dry right away, freezing may be necessary.

Treatment of art on paper must be done by qualified conservators specializing in paper, not by those who claim to treat all types of objects. Some conditions need immediate attention, while others can wait. Wet or mouldy materials or those with actively flaking media have high priority. So do brittle or fragile papers in danger or splitting or tearing. Because they can stain within months, recently applied self-stick tapes or labels should be removed immediately. Objects stuck onto brittle or acidic mounts should be attended as soon as possible. When in doubt about the urgency of treatment, it is more advisable to consult a professionally trained conservator first.