Using quality materials and adopting practices which minimise damage to paper-based materials are preferable to applying remedial treatments to these objects. The susceptibility of paper to deterioration however, means that a discussion of some of the available treatments is necessary.
As with all conservation treatments, a thorough assessment of an artefact's condition is essential before any treatment is applied. It is also important to test any potential treatment on an inconspicuous part of the object to minimise further damage or loss.
Familiarise yourself with the particular technique to be used by applying it to an expendable piece. Where there is any doubt about the condition or the treatment of an object, consult a conservator.
Invasive techniques such as washing, de-acidification, bleaching and use of solvents should be left in the hands of a conservator. De-acidification can cause certain papers to darken and bleaching may fade colours or delaminate certain paper types. Do not use ordinary household bleaches and peroxides under any circumstances. Approach the numerous published recipes with care as they may no longer be appropriate due to continuous modification of treatment procedures. Consult a conservator before attempting any treatment.
There is no such thing as a routine or standard treatment. Each object deserves special attention that takes into account condition, age, constituents, manufacture, origin, colour or discolouration and so on.
Carry out pre-treatment tests carefully to ensure that the object can withstand a particular action. For example, test each colour and ink individually to assess the solubility of dyes and to ascertain the suitability of the proposed treatment. Some colours may be stable at low relative humidity levels but bleed when exposed to prolonged high relative humidity levels.
The first step in most cleaning treatments is to remove dust and dirt. If paper is dirty but has no other signs of deterioration, such as flaking or brittleness, it may be surface cleaned.
Surface cleaning may be achieved by using:
- a soft brush;
- a soft, high quality eraser;
- grated eraser; and
- proprietary document cleaners.
A soft brush, such as a squirrel or cosmetic brush, can remove dust. Be careful however as dust particles can be quite sharp or may smear.
If brushing is not effective, try a soft, high quality eraser, but only after the type of media has been established. For instance, charcoal or pencil drawings and pastels cannot be cleaned in this way and care must be taken to avoid smudging inks and scuffing paper.
When erasing, use even strokes, going in one direction or rotating movements, covering only small areas at a time. This will minimise the risk of slipping or crushing. Use a thin, flexible slice of eraser to reduce pressure on the document. Wear a disposable latex (rubber) glove on the hand holding the document to avoid the transfer of grease and perspiration. Alternatively, wash hands before treatment to ensure they are grease-free.
Grated eraser also may be used to remove dirt. Finely grate an art eraser or cleaner (for example, Artgum, Faber Castell) using a plastic kitchen grater. Plastic is preferred as the metal variety may rust or shed small metal particles, which could damage the paper. Spread the resultant grains over the paper and lightly rotate these with the palm of the hand or the flat of the fingers until the entire area has been covered. Then brush the residue off the paper.
An alternative is to use a commercially available, non-abrasive document cleaner. Draft Clean Powder is similar to the grated eraser discussed above and is used in the same way, but the granules are of different sizes and textures. Fine powder is mixed with coarser and firmer particles but with some extra care it can be used safely.
Document Cleaning Pads use the same ingredients as the Draft Clean Powder but are ground more finely. The powder is held in a cloth pouch and with manipulation is released onto the document. With circular motions of the pouch, dirt and dust are absorbed. Dirt is not transferred to the object even though the cloth becomes dirty during the cleaning process.
As the object is obscured by the pad or the palm of your hand during the cleaning process test this method in an inconspicuous area before using it. A potential disadvantage of these techniques is that residues of the fine powder may remain in the paper grain after cleaning.
Clean books by using a dry lint-free cloth or a soft brush. The use of a low suction vacuum cleaner, such as a car cleaner or one with variable suction control, may be suitable for books in very good condition but this should be discussed with a conservator before taking action.
Brushing is the preferred method as it is easily applied and controlled. Always brush dust away from the spine of a book and away from yourself to avoid breathing in dust particles or mould spores.
Should the use of a vacuum cleaner be suitable, cover the nozzle with a piece of loose weave cloth (for example, cheesecloth, gauze) and hold it a few millimetres above the paper surface. This prevents scratching and will also stop any pieces from being accidentally sucked into the vacuum cleaner.
Due to the complex composition of paper-based materials such as books, maps and stamps, apart from removing surface dust, only attempt treatment after consultation with a conservator. The mix of leather, paper, fabric, adhesive, dyes, inks and pigments found in these objects means that any treatment must be considered very carefully.
Removing Residual Sellotape Glue
Where the plastic carrier of Sellotape is stuck to the paper, a conservator is needed to remove it safely. This carrier often becomes detached with age, leaving behind the sticky adhesive. This is undesirable as it is unsightly, attracts dirt and pages could stick together.
To remove the sticky residue rub a piece of crepe rubber (available from art and craft stores) in light circular motions over the particular area. This will gather the adhesive in a small ball, which can then be carefully lifted with tweezers.
This method can only be used on strong, sturdy papers as brittle and fragile papers are likely to be damaged during this process. The stain left by the adhesive however, will remain. Removing this stain will require a qualified conservator to apply chemical treatments. In many cases it is not possible to remove the stain.
Interleafing with acid-free or buffered tissue paper is a protective measure that will counteract acidity to a certain extent, especially if the documents are then stored in boxes or folders manufactured from archival materials. Interleafing also minimises abrasion between documents.
High acidity levels may be countered to some extent by placing affected papers in an alkaline or neutral environment such as that afforded by boxes or folders.
Cut buffered or unbuffered acid-free tissue paper used for interleafing to a size slightly larger than the document in question. If the documents are of varying sizes, cut the tissue to the dimensions of the largest document. This will prevent slipping and ensure there is complete coverage of the documents. The resulting documents can be stored in a folder or box that has been made to size. Do not cram too many items into one box or folder.
Certain pages of books can be interleafed with unbuffered acid-free paper, especially where transfer of images, inks or smudging may be a danger. Take care to limit interleafing to a few pages as too much added bulk will put pressure on the spine and make the pages gape.
Damp or Waterlogged Paper
If an object is damp or wet, dry it out as quickly as possible using fans or hairdryers on a cool setting. Keep papers flat and held in place as any movement could cause further damage. Hold books upright with the pages opened as evenly as possible.
An even more critical situation involves complete waterlogging, which may follow flooding of a storage area. For books, insert sheets of blotting paper, slightly larger than the book pages, every fourth or fifth page so that excess water is absorbed.
If large numbers of paper objects are involved, freeze items that cannot be treated immediately. This will minimise further damage through prolonged wetness and possible mould attack. Wrap single items in plastic and defrost and treat individually at a later date.
If mould is present on paper, quick action is necessary to prevent damage. To avoid the spread of fungal spores, isolate the object immediately in a plastic bag.
As slightly damp conditions are usually needed for mould to develop, allow the object to dry partially before further treatment is attempted. This will make it easier to remove the mould. Dry the mould-affected object in a well-ventilated area, such as a fume cupboard or outside.
After partial drying, remove visible mould with a soft brush using gentle strokes away from the person to avoid inhalation of fungal matter. Treat each page of an affected book. If the paper is fragile or flaking, or fumigation is required, consult a conservator.
Mould is difficult to treat and even low oxygen and freezing techniques may not be effective. Do not use thymol or other commercial fungicides as it can permanently damage and discolour paper. It is important to seek professional help.
After treating the object and cleaning the previously occupied storage space, ensure there is no recurrence of the conditions that allowed the mould to develop in the first place. Regular, careful cleaning and preventive conservation are the best solutions (see the chapter Mould and Insect Attack in Collections).
Framing an object can be of benefit if it is done properly. Framing protects paper objects from external hazards like dust and handling and provides a relatively stable environment. Use UV-absorbing acrylic to protect the object from damaging ultra violet light. Great care has to be taken when framing pastels, charcoal or chalk drawings and any work on paper that has flaking paints or a similar friable surface as the electrostatic nature of acrylic can cause damage. UV-absorbing acrylic does not protect against the damaging effects of white light present in daylight and artificial lights. Special precautions should be taken to hang framed works so that they are not adversely affected by such strong light (see the chapter Preventive Conservation: Agents of Decay).
Use archival quality materials for all framing. Never glue framed objects to their backings regardless of the quality of that backing. Different types of boards and papers expand and contract at different rates as the environmental conditions change. This could cause paper to tear or distort. Instead, hinge paper with suitable tapes so that the paper can move freely.
Framed objects should never touch the covering glass or acrylic as this may cause transfer of paint or print media to the glass/acrylic. A margin can be created by using a window mount or spacer inserted into the rebate of the frame.
It is best not to place framed works against external walls as these vary more in temperature and relative humidity than do internal walls. If there is no alternative, attach a spacer to the back of the frame to produce a suitable gap to increase the airflow around the framed work.