Document restoration covers a wide range of interventions — from gently flattening a crumpled letter to consolidating the fragile remains of a water-damaged ledger. The scope of any treatment should be proportional to the significance of the material and the skill of the person carrying it out. The principle that underlies all sound conservation practice is reversibility: every treatment should be undoable by a future conservator without additional harm to the document.
Assessment Before Treatment
Before touching a damaged document, note the following in writing or with photographs:
- The type and extent of damage — tears, folds, water staining, mould, losses
- The media on the sheet — iron gall ink, graphite, pencil, watercolour, typewriter carbon
- The paper type — handmade laid, machine-made wove, coated stock
- Any previous repair attempts — visible tape residue, patches, or consolidant
This record is useful if a question arises later about the condition of the document before treatment began. It also helps identify treatments that are inappropriate: a page with extensive watercolour wash cannot be safely humidified using an open water bath, for example.
When to refer to a professional: Items with significant monetary, legal, or historical value — land records, original artwork, rare printed books — should be assessed by a professional conservator before any treatment is attempted. The Canadian Association of Professional Conservators maintains a directory at capc-acrp.ca.
Humidification and Flattening
Rolled, folded, or distorted paper must be humidified before it is flattened. Attempting to flatten dry brittle paper by force causes fibre tearing along the existing distortion lines.
Passive humidification
The safest method for most materials. Place the document inside a sealed plastic container over — not touching — a layer of damp blotter paper or a shallow tray of water. The document absorbs moisture from the air inside the container. Check every 15–20 minutes; the paper should become relaxed and pliable but never feel damp to the touch.
Gore-tex humidification
For highly water-sensitive items, a Gore-tex membrane placed between the document and a damp surface allows moisture vapour to pass through while preventing direct liquid contact. This is the standard approach for documents with fugitive inks in professional conservation studios.
Flattening
Once the paper is relaxed, place it between dry blotters and then between boards under an even weight. Change the blotters after one to two hours to remove absorbed moisture and prevent the paper from re-distorting as it dries. A full drying sequence typically takes 12–24 hours under moderate weight.
Removing Old Tape
Pressure-sensitive adhesive tapes — Scotch tape, packing tape, masking tape — cause significant damage to paper over time. The adhesive yellows, migrates into the paper fibres, and becomes increasingly difficult to remove. Earlier removal generally produces better results.
Mechanical removal
On stable, non-fragile paper, the tape carrier (the plastic or fabric backing) can sometimes be peeled away using a microspatula or a thin Teflon tool. Work slowly, keeping the angle of peeling low. The adhesive layer usually remains on the paper after the carrier is removed.
Solvent removal of adhesive residue
Heptane or hexane are the solvents most commonly used to dissolve pressure-sensitive adhesive residue in conservation practice. Both are available from conservation suppliers. Apply a small amount to a cotton swab and dab — do not rub — along the adhesive edge. Test on an inconspicuous area first. Solvent should not be used near iron gall ink, as some solvents affect iron gall compounds.
Tear Repair
Small tears can be consolidated using thin Japanese tissue paper and wheat starch paste or methyl cellulose. Japanese tissues are available in a range of weights from conservation suppliers; a tissue weight close to or slightly lighter than the paper being repaired is appropriate for most documents.
Procedure
- Align the torn edges carefully and hold them in position under a weight or with fine weights placed along the tear.
- Tear — do not cut — a strip of Japanese tissue slightly wider than the tear. Tearing produces a feathered edge that integrates more invisibly than a cut edge.
- Apply a thin, even coat of wheat starch paste to the tissue strip using a fine brush.
- Position the tissue over the tear on the verso (back) of the document. Smooth from the centre outward with a microspatula.
- Cover with a release membrane and dry under light weight for several hours.
Losses and fills
Where paper is missing entirely, a fill of toned Japanese tissue can be inserted to stabilise the surrounding area and reduce the visual disruption of the loss. Matching the tone of the fill to the surrounding paper is achieved by tinting the tissue with watercolour before application or by selecting tissue from a range of pre-toned options available from conservation suppliers.
Mould Damage
Mould on paper is a serious problem. Active mould — identifiable by colour (green, grey, black, or white fuzzy growth) and sometimes by a musty odour — must be isolated immediately to prevent spread to adjacent materials.
- Isolate the affected item in a sealed container or bag and keep it in a cool, dry area below 18°C and 45% relative humidity.
- Do not attempt to clean active mould at home without appropriate respiratory protection and gloves.
- Once the mould has dried (become inactive), surface deposits can sometimes be removed with a soft, dry brush in a well-ventilated space.
- For significant mould damage, professional treatment or freeze-drying may be necessary. Library and Archives Canada's preservation resources describe institutional responses to mould events.
Housing and Long-Term Storage
A treated document is only as secure as the environment it is returned to. Correct housing slows re-deterioration and reduces handling risk.
- Use acid-free, lignin-free folders and boxes. Standard manila folders are acidic and will transfer acid to the document over time.
- Store items flat when possible. Vertical storage of unboxed documents allows sagging and distortion.
- Interleave fragile items with acid-free tissue to prevent surface contact between sheets.
- Label storage enclosures on the outside; never write directly on a document or its enclosure with a ballpoint pen, which can indent the surface.
Archival enclosure materials are available in Canada through Gaylord Archival, University Products (ships internationally), and the Canadian Heritage Information Network, which publishes a guide to institutional suppliers.