Introduction to storage and display materials
This page provides an introduction to choosing and using storage and display materials in a museum. It outlines how to choose safe, inert materials for museum storage and display, and avoid those that can cause chemical, physical, or environmental damage to collections.
This guide explains how materials interact with objects and outlines best practice for protecting collections through appropriate packing, storage, and display choices.
Introduction
Choosing the right materials for the display and storage of your items is an important way you can care for your collections. It helps provide security, support, and robust, inert barriers against physical, biological, or chemical damage.
Effects of storage and display materials on collections
Some storage and display materials that may seem suitable can damage museum collections, especially when the wrong materials and objects are combined in enclosed spaces.
Some storage and display materials unstable chemicals that react with objects. contain unstable chemicals which may react with objects. These reactions can cause corrosion, discolouration, and general deterioration. Damage may occur through harmful vapours or direct contact, which can happen more quickly at high temperatures and relative humidity.
Harmful substances and hazardous materials
Harmful and volatile substances include:
- Formaldehyde, acetic acid, formic acid, sulphuric acid, sulphur dioxide, nitrogen dioxide, ozone, and ammonia gas.
- Sources of these substances include wood products, acrylic resins, paints, lacquers and varnishes, glues and adhesives, pesticides, insecticides, fungicides, furnishing fabrics, adhesive tape and other sticky materials such as “Plasticine” and “Blu-tack”.
- Electrical machinery such as electrostatic air cleaners and some photocopying machines may produce ozone, which in turn breaks down molecular structures over time. Make sure they are fitted with filters and maintain ventilation of spaces.
- Burning fossil fuels can produce harmful vapours and air-borne soot particles that can affect collections. More information is available in the Identifying and reducing air pollution guide.
How museum objects react
Metals
All metals are affected by harmful vapours (volatile organic compounds, VOCs) released by wood and wood-based materials, though some more than others. Pay particular attention to lead, which corrodes from acetic acid in woods such as oak. This is also a risk for stained glass, lead tokens in oak-lined drawers, and copper alloys when exposed to pollutants like formaldehyde. Formaldehyde can be found in adhesives, particleboard, off-gassing specimen preservation collections.
Silver and copper objects, metal embroidery threads, sequins, and silver photographic images can tarnish due to sulphur gases released by wool. Acids and salts from leather materials can also cause corrosion, tarnishing, and powdery surface deposits.
Archaeological metals may be affected by pollutants during and after excavation. Some form aesthetically desirable patinas, while others corrode and obscure the object. Post-excavation corrosion is especially damaging and is accelerated by high humidity.
Magnetic tapes
Magnetic tapes are found in cassettes, reel-to-reel films, and computers. They are prone to physical and chemical deterioration, especially from moisture absorbed into coatings, binders, or the tape itself. Magnetic particles can also lose their charge or degrade through overuse, causing physical wear.
Paper
Paper objects, such as books, maps, prints, drawings, watercolours, letters, and charts, are vulnerable if made from poor-quality acidic materials, especially those containing lignin or wood pulp. They can discolour, become brittle, stain, and deteriorate when mounted in acidic boards or stored in poor environments. As they break down, they release harmful acids that can affect other materials.
Adhesive tapes (e.g. Sellotape or masking tape) shrink and eventually detach, leaving sticky yellow stains. These are difficult or impossible to remove and continue to damage the paper.
Photographic material
Photographs, slides, prints, and negatives are affected by vapours and plasticisers from polyvinyl chloride (PVC) and other plastics. Daguerreotype plates tarnish due to sulphur gases. Paper prints may oxidise in polluted environments, causing a bluish metallic sheen known as ‘silver mirroring’. Wooden storage can off-gas, absorb moisture, and harbour mould, which can transfer to photographic materials.
Textiles
Textiles deteriorate faster when in contact with acid-releasing materials such as cheap mount board, boxes, or acidic rollers. Metal hangers can corrode or snag fibres. Display fabrics may also cause damage, as dyes and fire-retardant treatments can lead to fading.
Pins and tacks used in framing can rust due to moisture in fabrics, causing further damage.
Bone and ivory
Bone and ivory can deteriorate when exposed to vapours from rubber, urethane foam, vinyl flooring, adhesives, carpets, and acidic wood or paints. Volatile sulphur compounds from rubber can cause yellow or orange discolouration in ivory.
Some imitation ivories, such as French ivory, are made from cellulose nitrate or casein. When deteriorating, they should be isolated from the rest of the collection. Degrading cellulose nitrate can release acidic and oxidising gases.
Organic plastics, rubber, and latex
Organic plastics (e.g. cellulose acetate, cellulose nitrate, celluloid, Bakelite, Catalin, Casein, Lucite) and early rubbers (e.g. ebonite, latex, gutta-percha) are highly unstable. Environmental factors can cause embrittlement, pest damage, and decay. These materials may release harmful VOCs, such as acetic acid or sulphur compounds.
They are sensitive to plasticisers in materials like PVC sleeves and wraps. Exposure to oxygen, light, and fluctuating temperatures can break down polymers, causing separation and surface changes.
Ozone from electrical equipment and some metals accelerates rubber deterioration. Some rubber and latex also contain toxic pigments, such as lead, and may become sticky as they degrade. Cellulose nitrate is especially hazardous due to its flammability and release of toxic gases.
Pigments
Pigments on paper, feathers, textiles, and ethnographic objects can fade or discolour when exposed to acidic vapours, sulphur gases, plastics, or poor-quality cardboard.
Wood
Many types of wood release formaldehyde, which can create formic acid. As a vapour, this acid can corrode metals, ceramics, and organic materials. Wooden objects continue to emit VOCs over time, although this reduces gradually.
Planning for materials
Use inert materials whenever you can in a museum. This may involve additional storage and display costs but helps to preserve your objects.
If you’re working with a limited budget, replace the unsafe materials gradually when you can afford to. Start with materials near the most vulnerable items first. If you’re in any doubt about using a material, get a small sample tested before placing it in your museum.
Look to use materials for storage and display that include:
- Materials that do not abrade, rust, or are not fibrous or could physically damage an object
- Materials that have not had finishes e.g. fire retardant coatings that could cause chemical reactions
- Materials that have not been dyed, or are not colourfast and could transfer to another item
- Materials that might leave a residue e.g. tape or blu-tack
- Materials that can off gas as they break down e.g. sealants, rubber, or plastic materials and cause corrosion or discolouration
Some further examples and substitute material can be found in Collections Trust’ guide, Materials for storage and display.
Choosing safe materials
There are two categories of materials:
Materials used to protect, shape or support the object
These materials are in direct contact with objects. They protect against dirt, dust, and other harmful factors. They also help maintain an object’s shape. Because of this, they must be chemically stable and free from harmful substances.
Materials for physical storage and display
These include shelves, cupboards, cabinets, and display cases. They create a safe environment and help protect objects from air pollution, dust, temperature and humidity changes, light (in storage), and security risks. Our guide on Identifying and reducing air pollution contains advice on managing airborne pollution in museums environments.
Although these storage and display materials are not in direct contact with objects, they must still be safe. Harmful substances can build up in enclosed spaces such as cases and cupboards. This can damage objects over time. Museum containers should protect objects from air pollution and environmental changes. They must also be inert and stable. Microclimates within display cases can trap harmful substances, so material choice is essential.
Where possible, use materials that can be reused or recycled.
Examples of safe materials for packing and storage
Using appropriate materials is essential for protecting museum objects during storage and handling. The examples below highlight commonly used, stable materials that provide physical support and create safe, inert barriers against environmental and chemical damage.
Acid-free tissue is used for interleaving when rolling or storing flat items, as well as for wrapping or padding three-dimensional objects and supporting textiles to reduce handling.
Use tissue made from cotton, linen rags, or highly purified wood fibres without acid-producing lignin. It is often labelled ‘acid-free’, ‘museum-quality’, or ‘archive-quality’, but you should always check its acidity before use.
Some acid-free tissues contain alkaline buffers that help prevent acidic damage to paper objects. However, these can be harmful to certain materials and should not be used with photographic materials or textiles.
Melinex is a transparent polyester sheet available in a range of sleeve sizes, suitable for storing photographic materials and paper items. It should not be used for items with loose media, such as pastel or charcoal drawings, as static can lift the media.
It is also available as a continuous film that can be heat-sealed to create custom sleeves. Melinex is highly durable and, if uncontaminated, can be fully recycled.
Polythene self-sealing bags come in various sizes and are suitable for storing small items. They are free from coatings and plasticisers, making them fully inert.
Avoid polyvinyl chloride (PVC) or plastics containing chloride or nitrate, as they release harmful vapours. Polythene offers long-term protection and can be recycled.
Tyvek is a high-density polyethylene (HDPE) fibre sheeting that resists water penetration from the smooth outer surface to the rough inner surface. It remains breathable, allowing air to pass in both directions.
It is commonly used to make dust covers for costumes, upholstered furniture, and rolled textiles. As it is made from HDPE, Tyvek is 100% recyclable.
Acid-free board
Use acid-free board when mounting prints, drawings, and other objects. It can also be used for storage, as some boards are buffered to prevent acid migration.
Buffered board should not be used for photographs or textiles, as it can cause damage.
Ethafoam and Plastazote are stable polyethylene foams made using an inert nitrogen gas. They can be cut and shaped to create supports for three-dimensional objects.
They come in various colours, but only black and white are safe for use, as other colourants may stain or damage objects. These foams can be reused, offering some sustainability benefits.
Perspex (polymethyl methacrylate) can be moulded into mounts for small glass, ceramic, and other stable objects. It can be difficult to work with and should not be used with adhesives that release harmful vapours.
Although useful, Perspex is being phased out in favour of more sustainable and reusable mounting materials.
Examples of safe materials for shelving and containers
The right materials in museum containers protect objects from air pollution and fluctuating environmental conditions. Containers should be made from inert, stable materials, as harmful substances can build up quickly in the enclosed microclimates of display cases.
Many museum stores retain old exhibition mounts and display panels. If these contain potentially harmful materials, keep them wrapped or stored away from vulnerable objects.
Metal is the preferred material for display cases, shelving, and cupboards. It is strong, smooth, inert, non-flammable, and does not emit harmful vapours.
Always protect metal surfaces to prevent rust. Use baked enamel finishes rather than paint.
Wood emits harmful vapours, including formic and acetic acids and peroxides. Fresh or unseasoned wood is especially damaging.
For showcases, use well-seasoned, low-emission woods such as spruce (excluding Sitka spruce), poplar, basswood, walnut, elm, magnolia, or yellow pine. Avoid oak, sweet chestnut, western red cedar, Douglas fir, and teak, which emit more harmful compounds.
Iron and steel are particularly vulnerable to corrosion from wood emissions, although teak can also affect more resistant alloys.
Plywood, chipboard, and particle board release similar harmful emissions to wood, as well as formaldehyde from adhesives. Medium density fibreboard (MDF) emits lower levels but still poses a risk.
The release of acids from wood products can’t be avoided entirely. Use barrier foils, scavengers, or sorbents to reduce emissions. Seal exposed edges carefully, as they release vapours more quickly.
Paints, lacquers, and varnishes do not provide effective vapour barriers and may introduce additional risks if unstable.
Avoid slow-drying or high-VOC finishes such as casein, alkyd, oil-modified paints, and some polyurethanes. Acrylic emulsions and epoxy resins are safer options, but must be fully cured before use.
Never place objects directly on painted or varnished surfaces. Use a barrier material such as Melinex or Plastazote.
Many lightweight boards contain inner material such as polystyrene and a skin of acid-free paper, plastic, or aluminium or adhesives that release harmful gases.
Use barrier foil to seal them or choose alternative materials where possible.
Wool, fire-retardant fabrics, and foam- or adhesive-backed textiles can emit harmful vapours. Avoid these where possible.
Use undyed, unbleached cotton or linen. Wash thoroughly before use with a gentle detergent. Avoid detergents with bleach or added softeners. Test dyed fabrics for colour fastness before use by rubbing the fabric first with a dry piece of white cotton, and then with a piece of damp cotton.
Glass is an excellent material for museums. It is impermeable to gases, scratch resistant, and can be fitted with UV filters or laminates. However, it is heavy and may generate static during cleaning. High humidity can cause condensation and mould growth which is harmful to both organic materials and people.
Use glass that meets British Standards for safety, especially in large panels. Avoid vinegar based cleaning agents or anything harmful chemical substances.
These materials are lighter than glass and often include UV protection, making this useful for light sensitive items. They are impact-resistant, cracking or bending instead of shattering.
However, Perspex is more permeable to gases, scratches easily, and can generate static that attracts loose items in containers. It is also less rigid than glass.
Check all adhesives, seals, gaskets, and labels before use in display and storage. Ensure they do not contain harmful substances, require curing, are non-reversible and will not cause long term issues with pests.
Common materials include:
- EVA hot-melt glue such as ethylene/viynal acetate EVA copolymer types (not in direct contact with objects)
- Bubble wrap is suitable for short-term use only, applied bubble side out with a tissue barrier
- Correx (corrugated plastic sheet) for bespoke durable, waterproof storage boxes
- Polyethylene foam (Jiffy) for lightweight, inert, shock-absorbing cushioning
- Tapes and ties include unbleached cotton tape, masking tape, scotch tape, string or webbing straps. Ensure any tape that could leave a sticky residue is not in direct contact with objects and use suitable plastic ties
- Polyethylene sheeting and bags for sheeting can be useful for emergency planning, dust covers and for wrapping to maintain good environmental transition during transport. Bags can be used to store items to reduce handling and allow for information to be written on. Keep out of direct sunlight to prevent moisture/sweating
- Plastazote (dense polyurethane foam)
- Cross-linked polyolefin gaskets without additives such as dyes or flame retardants
- Tyvek for covers, supports, labels, display panels, dust sheeting, and long-term storage, especially for textiles and upholstered items
- Acid-free paper labels and mounts, adhered using wheat starch paste or ethylene vinyl acetate (EVA)
Materials of museum objects
Museum objects can themselves contain materials that are harmful to other items and the rest of the museum. Modern organic materials are likely to release harmful gases. Badly processed photographs can emit acidic or sulphuric gases that lead to discolouration and weakening of the paper. Celluloid objects release vapours that speed up their own deterioration.
These processes particularly occur when the objects are kept in a confined space, such as display cases or plastic boxes, as harmful vapours build up. Such objects require display and storage that allows air-exchange. Wrap them in acid-free tissue to absorb emitted gases and store them in a separate part of the storage area where there’s adequate air exchange.
Further information
Pollutants in the Museum Environment (Hatchfield, P. Archetype, 2002, ISBN 1873132964) is a helpful book for in depth reading on preventing pollution.
The Collections Trust website collates an extensive list of advice guides on collections care.
National Museums of Scotland have created an online training course on object packing.