Care for works on paper

Works on paper, drawings, prints, photographs, watercolours, manuscripts and archival documents are among the most vulnerable objects in any collection. They respond to light, moisture, handling and the materials they touch. The method below is built around one decision rule: when in doubt, reduce change. Paper wants a stable environment, low light and minimal handling. Everything else follows from that.

the material below is not connected to the former TSB Bank Wallace Arts Centre or the James Wallace Arts Trust, and does not speak for them. It is an independent guide.

Care for works on paper: The one rule that governs everything

If you can control light, moisture and handling, you have solved most of paper conservation.

Every other factor (framing, storage, pests, transport) is a variation on those three. When you are unsure what to do, ask: Does this action reduce light, stabilise moisture levels, or reduce physical contact? If the answer is no, do not do it.

Paper conservation reduces to a single decision rule: when in doubt, reduce change, because paper wants a stable environment, low light and minimal handling, and everything else follows from that.

Light

Light damage is cumulative and permanent. It cannot be reversed, only prevented. The damage is caused by ultraviolet (UV) radiation and, to a lesser extent, visible light. UV fades pigments and darkens paper fibres; visible light adds to the same effect, though more slowly.

The international guideline for light-sensitive works on paper is 50 lux (about the light of a dim hallway) and no more than 50,000 lux-hours per year (Canadian Conservation Institute, 2017). For comparison, a typical living room in daylight can reach 300-500 lux. A work on paper placed in direct sunlight for a few hours a day can exceed a year’s safe light exposure in a single afternoon.

Practical light controls

• Use UV-filtering glazing (museum glass or acrylic with UV protection) and keep works off walls that receive direct sun.
• No halogen spotlights, and no LED strip lights mounted inside the frame.
• If you cannot measure lux, use the hand-shadow test: if a hand held between the light source and the work casts a sharp shadow, the light is too strong.
• Rotate works every three to six months to limit cumulative exposure. Store the off-display work flat in an archival box between layers of acid-free tissue.
• For photographs, a 200 lux limit is a reasonable benchmark; for works on paper, the benchmark is 50 lux.

Moisture and relative humidity

Paper is hygroscopic: it absorbs and releases moisture. Rapid swings cause cockling, warping, foxing and mould. Sustained high moisture levels invite mould; sustained low levels make paper brittle. Fluctuations are more damaging than a steady reading slightly outside the recommended band.

The recommended range for mixed collections is 45-55% relative humidity, with a 24-hour fluctuation of no more than ±5% (Canadian Conservation Institute, 2020). The Museum of Fine Arts, Boston, recommends 45-55% RH and 18-22°C for mixed collections.

Practical moisture controls

• Use a digital hygrometer near the work and monitor seasonal changes. Do not guess.
• In Aotearoa, humid coastal climates mean a dehumidifier in winter may be necessary. In drier parts of the South Island, over-dry air can make paper brittle and should be moderated with humidifiers or microclimate boxes.
• Avoid placing works near bathrooms, kitchens, vents, fireplaces or single-glazed windows. The microclimate near a single-glazed window can swing 20% RH within a day.
• Do not hang works on exterior walls in older homes. If you must use an exterior wall, fit a spacer frame to allow airflow.
• For high-value works where moisture levels fluctuate, a microclimate frame with sealed backing and desiccant is a practical intervention.

Temperature

The lower the better for chemical stability, but human comfort sets the limit. Stable room temperature is the goal; there is no single correct temperature, but a range of 18-21°C is commonly cited. Avoid attics, garages and uninsulated exterior walls. Keep works away from heat sources such as radiators, fireplaces and direct sunlight.

Handling

Always handle works on paper with clean, dry hands. Oils and acids from fingers cause permanent marking. Wear clean cotton or nitrile gloves for photographs, pastels or any work with a fragile surface. Support the full sheet with both hands or a rigid board when moving it. Never touch the surface of a painting or drawing; handle only the edges or the back.

Handling rules

• Remove rings, bracelets or anything that might scratch.
• Avoid eating, drinking or smoking near works.
• Use two people for anything larger than a metre. Carry it flat and avoid rolling unless the paper is designed for it.
• Never use self-adhesive tape, pressure-sensitive tape, pins, adhesives or rubber bands on or near the artwork.

Storage

Store flat in acid-free folders or boxes. Flat files or archival boxes are ideal. Separate works with acid-free interleaving tissue. Do not stack works directly on top of one another without protective interleaving.

Storage rules

• Keep storage areas dark, cool and stable. Avoid basements, attics and areas near exterior walls.
• Keep storage boxes off the floor to avoid flood and pest risk.
• For framed works, store upright with rigid backing boards, never flat under heavy objects. If you must stack framed works flat, use soft padding between frames and keep the stack small.
• If a work must be rolled, roll it with the image facing outwards on an archival tube and support the entire length. Never store a rolled work resting on its rolled edge.

Framing

Use archival, museum-grade materials: UV-filtering glass or acrylic, acid-free mats and conservation-grade backing boards. Do not let the artwork touch the glazing; use a mat or spacer.

For works on paper, hinging with Japanese paper and wheat starch paste is the conservation standard; pressure-sensitive tape is never acceptable. For works on canvas, framing is optional but if framed, the canvas should not touch the glass. For Māori and Pacific works, framing and display decisions should be made in consultation with the artist or community where possible, as some materials and images carry cultural protocols.

Pests, pollutants and display placement

Keep works away from food, smoking and areas where insects or rodents are active. Silverfish and cockroaches are the most common threats to paper in Aotearoa; their presence is a sign to check storage areas and consider traps or professional pest control. Do not use mothballs or naphthalene near artworks; they can damage frames and paper.

Hang works away from high-traffic areas. Use picture hooks and hanging systems rated for the weight; for heavier works, use two hooks and a wire rated to at least three times the weight. Never place works directly under a skylight or in a room with strong afternoon sun. For unframed works on paper, exhibit only under glass with archival matting.