Selecting Materials for Storage and Display
Collections caretakers such as Collection Managers, Curators, Registrars, Archivists and Librarians often have to make difficult decisions regarding appropriate storage and display materials for the preservation of the historical and artistic materials under their care. It is essential that they choose materials that properly house and support artifacts without causing damage or deterioration. However, navigating a museum or archival supply catalog can be difficult. To further complicate decision making, many materials marked “archival” or “acid-free” available through catalogs or in office supply and craft stores may not necessarily be appropriate for the long-term preservation of collections.
The following tables show what materials are acceptable for use in the display and storage of collection objects. Please note that many of these materials may be marketed under different product or trade names. When choosing products, if the material-type is unclear or if there are questions about its suitability for use with collections, contact the manufacturer and/or a conservator.
PLASTICS
Not all plastics are suitable for use with collections. However, stable plastic materials that do not off-gas can be an ideal material for safely housing collections items, easing handling, and providing support. Bags, containers, boxes, and sheeting made of appropriate types of plastics all have useful applications in museums, galleries, libraries, and archives.
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Material Type |
Material details |
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Polyethylene (polythene) |
Used to make storage bags, enclosures, foams and sheets or as a spun bonded fiber product. Chemically inert and very stable. Sometimes marketed under the brand names of Volara®, Ethafoam®, Trirod®, Colara®, Correx® or Tyvek®. Be careful of moisture condensing on polythene sheets and use buffering materials such as acid-free tissue between the object and the sheeting. Polyethylene can also be cut into strips and used as straps to secure objects and books to mounts. |
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Polyester |
Available in sheets, bags, or enclosures. Sometimes marketed under the brand names Melinex®, Secol® or Mylar®. Sheets are sold under the brand name Remay®. Can be used for storage, and, being transparent, are also useful for handling paper artifacts. Polyester can be found in straps to secure artifacts to mounts. |
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Polypropylene (PP) |
Used to make boxes, bags, and enclosures. Corrugated polypropylene boards are manufactured under the brand name Coroplast Archival®. |
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Polymethyl Methacrylate (PMMA) |
Available in sheets under the trade name of Perspex®, Plexiglas®, or Lucite®. They can be used for glazing. They are scratch-resistant and low static, as well as UV filtering. |
Avoid using PVC (polyvinyl chloride) plastic because as it deteriorates, it gives off hydrochloric acid. The plasticizers used in PVC can affect photographic materials such as slides, prints and negatives as well as rubber materials and modern plastics. It is also best to avoid the use of cellulose nitrate, cellulose acetate (diacetate and triacetate) and polyurethanes.
FABRICS, THREADS AND PADDINGS
When selecting fabrics or padding materials, it is best to opt for undyed and sizing-free materials. Fabrics, threads and padding materials can be used to create custom storage solutions for textiles and to support objects within boxes.
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Material Type |
Material details |
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Unsized, unbleached and undyed cotton |
Can be purchased at any fabric supply store or in archival catalogs, and can be used for storage enclosures, padding, and in exhibition cases. Fabrics should be washed with a phosphate-free detergent before coming in contact with collections. Cotton can also be found as a non-medical grade, more elastic material called Stockinet®, which is helpful to stuff and create padding within boxes, or for covering exhibit mounts. Also available as unbleached calico sheets, which can be used as dust covers. Cotton can also be found as a twill tape, sold in different lengths and widths as well as undyed cotton string for securing objects. |
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Linen and jute |
Available in fabric supply stores. Can be used similarly to cotton, as listed above. Linen and jute contain more lignin and are more abrasive fibers than cotton, however, so it is best to avoid direct contact with the artifact. |
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Un-fused polyester wadding |
Available in fabric and craft supply stores. Useful as a stuffing material when creating padding and cushioned supports for collections. Ensure it is covered with washed, unbleached cotton calico to prevent fibers catching on the surface of objects and small objects being lost within. |
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Flexible extruded polyethylene or polystyrene foam |
Available in craft supply stores and through archival catalogs. Can be used to make supports within boxes and to support collections with round bases (baskets, pots) on shelves. Available under the name of Plastazote® and Ethafoam®. This material is inert and non-abrasive. Note that polystyrene can yellow as it ages. |
Avoid using wool and felt as they give off sulphur compounds that can tarnish metals, cause fading in feathers and ethnographic materials, as well as attracts insects. Do not use nylon threads or monofilament, also known as fishing line, because they fail and snap easily as they age. Fishing line, if used in direct contact with objects other than hard metals and glass, should be used with padding placed between the object and the line.
ADHESIVES
Adhesives, even those marketed as “archival,” should never be placed in direct contact with collections. Some tapes and glues can be used to make enclosures and to seal display cases.
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Material Type |
Material details |
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Sellotape and double-sided tape (only 3M 415 double sided tape) |
Sold in various widths for multiple applications. Can be used to make boxes and enclosures. |
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Ethylene/Vinyl Acetate copolymer adhesives: Hot Melt Glues or laminating emulsions such as EVACON-R. HMG Cellulose Nitrate adhesive, UHU Clear
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Specially formulated neutral pH, non-plasticized, reversible archival paper adhesives. Useful for making boxes and acid-free cardboard enclosures. Some of which have a life span of no longer than 6 months. |
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HMG Paraloid B72 Acrylic adhesive, Evode Epoxy Resin |
Can be used as adhesive for displaying object labels in areas where artifacts are present. |
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Polytetrafluoroethane (PTFE) tape |
Useful for the display of framed materials. It can be stretched around the edge of glass before it is inserted into place. The tape relaxes and fills the gap between the glass and frame so holding it in place. |
Be careful when using Polyvinyl Acetate emulsion (PVA) and Urea Formaldehyde adhesives because they give off acetic acid which can attack various materials, especially metals. Prior to their use, consider what kind of artifact will be stored in the enclosure where the adhesive has been used. Avoid using rubber adhesives as they give off sulphur and degrade by light exposure becoming brittle. Rubber sealants should also be avoided since they release acetic acid and harmful vapors.
PAPERS AND BOARDS
Paper and paperboards are used to make boxes, folders, support boards, and are also used as interleaving materials. These materials are marketed under several brand names. For museums, galleries, libraries, and archives collection preservation, materials that are marketed as both acid-free and lignin-free should be used. They can all be purchased from archival suppliers. Foamex® boards can be used for display panels and acid-free paper framing tape is also available.
Note that any papers or enclosures being used to store photographic materials should pass the Photographic Activity Test (PAT), which is a predictive test of reactions between an enclosure material and photographic material.
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Material type |
Material details |
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Acid-free paper, tissue paper, cards |
Papers marked as acid-free are pH neutral or slightly alkaline at the time of manufacture (pH 6.0 – 9.0). Many papers marketed as acid-free are made from wood pulp and will become acidic over time and deteriorate as they age, so it is important to check on them for acidity and replace when needed. |
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Lignin-free paper, cards |
Lignin is a material found in wood pulp and can cause yellowing and brittleness in paper over time. Lignin can be removed in the paper-making process, making the paper more suitable for collections storage applications. This final product can be named as cotton-based papers. |
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Buffered paper |
Buffering works to neutralize acids that may form in paper. Buffered papers are appropriate for most storage applications, but should not come into direct contact with blueprints, cyanotypes, silver and other metals, textiles, and animal-derived materials (silk, horn, bone etc.). Buffered papers include an additive, usually calcium carbonate 3%, to make the paper slightly alkaline (pH 7.5-9.5). |
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Unbuffered paper |
Unbuffered papers are pH neutral and do not contain any buffering agent. These papers are less effective at absorbing acids produced by the environment or objects than buffered paper. Appropriate for use in instances where more buffered papers might cause collections damage. |
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Zeolites paper |
Zeolites are molecular sieves that are imbedded into paper or paperboard. Zeolites trap gaseous pollutants either present in the environment or those produced by the deterioration of the artifact. Testing has shown that paper artifacts and photographic prints enclosed in papers containing zeolites are provided additional protection. Sometimes sold under the brand name Micro-Chamber®, these products are buffered. |
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Zero Grade MDF, Medite (MDF without binder), Sundela K Quality (not grade A), Marine Plywood |
These materials are acceptable as boards but should not be in direct contact with artifacts. They should be treated with barrier foil or acrylic varnish since they can be source of organic acids. |
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Acrylic and polythene boards |
Often found under the name of Perspex® and Correx®, these materials are stable and inert (see the above plastics table). They are solid strong resins that can be used to make mounts or supports instead of wood. |
Ordinary paper, tissue paper, gummed paper, Foamcore® and glassine photo envelopes become acidic over time causing organic objects in contact with them to discolor and deteriorate as well as accelerate metal corrosion and glass devitrification.
Wood and composite boards including plywood, chipboard, particleboard and hardboard should be avoided as they give off harmful phenol or urea formaldehyde which forms organic acids. Formaldehyde reacts with other materials to form formic acid, which is very destructive. Phenols and formaldehyde are also a heath hazard for people.
In case it might be necessary to use wood, it is important that the wood is sealed. Barrier foil is the best method: it is a gas impermeable metal foil sealed between layers of inert plastic film, such as PP004 (Moistop®) and Marvelseal 360®. Seal edges with aluminum tape. Do not puncture the foil. An alternative method is to use an acrylic varnish which does not give off harmful vapors. Dacrylate®, Sealbond RJ119® and Cuprinol Enhance® are suitable. Use at least 3 coats and allow them to dry thoroughly between applications.
When wood must be used, use seasoned spruce, mahogany, walnut, basswood, poplar, and balsa, or exterior grade plywood as well as MDF (medium-density fiberboard), with formaldehyde-free adhesives.
ATTACHMENTS, LABELS, COATINGS AND PAINTS
Collections materials will sometimes need labeling and attached documentation. It is imperative that self-adhesive labels are not used, as well as Velcro®, Blu Tac®, masking tape and sticky tape. Safe tested materials must be used for mounts, such as coatings and paints.
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Material Type |
Material details |
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Polyethylene sheathed metal pins |
Acceptable for use, if necessary. |
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Spun-bonded Polyester labels |
Also under the name of Tyvek® labels, can be tied on the materials using unbleached cotton tape or cord. |
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Ink and acrylic varnish (Paraloid B72®) dissolved in acetone |
Can be used to write accession numbers on protected areas in discreate part of the object. |
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Two-part Epoxy Resins |
Can be used as a sealant, and to cover floors and surfaces in storage areas as it is resistant to UV, shock and vibrations, corrosion, thermal cycling, and have low VOCs. |
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Anodized aluminum, powder-coated steel, chrome-plated steel, baked enamel (only if it has been tested for proper baking by performing a methyl ethyl ketone rub test) |
Any of these metals are acceptable to be used as meatal coating because they are resistant to corrosion, wear and don’t release any VOCs. |
Avoid using unsheathed metal pins that can cause accelerated corrosion if they touch metal objects or stain items they corrode directly. Any other metal that has not been sealed with appropriate sealants might also be susceptible to chemical off-gassing or corrosion and thus should be avoided. Do not use oil or latex paints and varnishes.
Any sticky substance or adhesive applied directly to an object is non reversible and can cause chemical deterioration. Pressure-sensitive adhesives will fail with time, and labels will be lost.
Updated Summer 2020.