Using Decorative Fabrics Inside Exhibit Cases

Category:Exhibition
Category: Exhibit Technical Notes
Category: Exhibit Case Design
Category: Exhibit Fabrication
Category: Standards & Guidelines
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Contributors: Members of the MWG's Materials Fact Sheet Working group; Jenifer Bosworth, Anne Ennes, Lisa Goldberg, Jamie Gleason, Jennifer Herrmann, Nancy Lev-Alexander, Patricia Silence, Catherine H. Stephens, and Theresa Voellinger
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== How are fabrics used in exhibits? ==
Fabrics are used as a design feature within exhibition cases or displays as well as wall coverings. They are used to cover panels, case decks and risers, and object supports. In addition to covering exhibit furniture, other examples include use for mannequin covers, textile supports, banners or interpretive panels that are included inside a case. Fabrics can be fastened to exhibit furniture or mannequins using sewing techniques, mechanical fasteners, or adhesives (primarily pressure sensitive double sided tape).
== Why are fabrics a preservation concern? ==
Fabrics are complex due to their combination of fiber type, dye stability, fiber/fabric treatments (fire retardants, anti-static agents, washing1, etc.), additives, and surface characteristics. In addition, fabrics may induce physical or chemical damage from off gassing or when in direct contact with objects. Evaluating these variables (and others) when choosing a fabric for exhibition use is critical in considering preservation in the exhibition environment. Also, careful evaluation of any adhesives used to fasten a fabric is necessary. 
===Fiber type===
* Volatile organic compounds (VOCs)2 are emitted by some fibers and therefore, fabrics based upon these fibers should be avoided:
** Wool is a sulfur-containing protein, which upon degradation, emits hydrogen sulfide gas which is corrosive to metals, especially silver.3 Silk is another natural protein based fiber. While it has almost no sulfur, silk may still not be the best choice for exhibit use.
** Cellulose acetate fibers can degrade to produce acetic acid.4,5
** Polyvinyl chloride-containing fibers, part of the group of fibers called vinyls, produce volatile hydrogen chloride when exposed to heat and light. 
* Polyester batting can be very abrasive but polyester fabrics tend to be smooth and dimensionally stable.
===Dye Stability (dyes, mordants and other dye bath components)===
* Dyes can sometimes bleed or rub off onto materials which come into contact with them. This dye transfer can occur through dry abrasion of the surface or when the fabric is exposed to water or solvents. 
* Specific dyes may release VOCs (as detected in Oddy Testing); some examples include direct dyes for cotton and linen using sodium chloride or sodium sulfate (which should be avoided).
* Dyes vary in light fastness; choosing a light-fast dye prevents premature replacement of the material.
* Note that dye abrasion/transfer, bleed, and light fastness can be tested prior to exhibition use. Oddy test results for many dyed fabrics can be found on the Materials Testing Results pages by filtering for fabric within Material Type.
===Fiber/Fabric Treatments and Additives===
====Size====
* Sizing additives such as starch, wax, or manufactured polymers (such as acrylic acid derivatives) added to fill the pores or surfaces of the yarn or threads in order to withstand the abrasive forces of the weaving or machining processes. Sizing can transfer to or react with display objects. Some sizing (starch) may attract pests.
====Chemical Treatments====
* Chemical treatment (mercerization or ammonia treatment) of cellulosic fibers/fabrics changes the product to impart a greater affinity for dyes, chemical finishes, and handling properties. Residual chemicals can cause deterioration problems.
* Permanent press treatments involve the application of chemical treatments like formaldehyde or synthetic resins to reduce wrinkling after washing. Fabrics that use formaldehyde  can degrade or release VOCs. 
* Fire retardant treatments use acidic chemicals, like urea formaldehyde and a variety of other chemicals (disodium phosphate, etc.) which degrade readily and become volatile.
* Anti-Static coatings should be washed out to avoid reacting chemically or physically with objects.8
====Adhesives====
* Adhesives6 used to attach fabrics to decking, backing boards, or other case furniture can emit harmful VOCs into the environment of a case7.
* Adhesives can fail if used for long periods of time and therefore require monitoring for replacement.
* See Adhesives Tech Note and CAMEO
====Surface characteristics====
* Abrasive fabrics and nap can cause abrasion to delicate surfaces.
* Fabrics can aid or inhibit the physical stability of objects. 
** Imperfections in the weave may prevent an object from resting securely on a surface.
** Napped fabrics such as velveteen, Ultrasuede®, or cotton flannel can help hold an object in place.
* Isolate metallic objects from direct contact with fabrics: objects should only come into contact with stable materials. Use polyethylene or polyester sheeting, or other inert materials as a barrier between the object and decorative fabrics of uncertain stability.
== What types of fabrics can be recommended for use inside exhibit cases? ==
Fabrics used as a case lining must be researched and tested, both for volatile chemical offgassing and for damage that can occur from direct contact. 
The Materials Testing Results page has an array of results for fabrics that have been Oddy tested. In addition to the Oddy test, examine fabric dyes for water solubility by blotting a piece of the wetted fabric with white toweling, or by immersing a sample in water for 15 minutes, then blotting. Some manufacturers do their own testing; cross compare results when evaluating a fabric for exhibition use.
Use the safest types of fabrics: 
* Unbleached cotton, linen, should not contain any foreign matter or processing chemicals.
* Synthetic materials have very low water absorbency or retention, and low abrasion qualities. 
** Polyester offers strength, abrasion and tear resistance. Polyester is the most commonly available synthetic fabric in the widest variety of weaves. 
** Nylon (polyamides) have similar characteristics to polyester.
** Acrylics are chemically resistant and strong.
== Preservation strategies ==
Practical measures to make the use of fabric in a display case safer.
* Prepare the fabric for use. Fabrics can be washed in a neutral detergent to remove excess dyes and finishes and to preshrink; to remove all residual dye, wash until the water runs clear.1 Some manufacturers will wash, dry, and iron the fabric prior to shipping if asked.
* Attach fabric mechanically; sewing, rust-proof staples, or tack pins can be used. 
* Avoid using adhesive when possible: archival-quality pressure sensitive adhesive tape is an option, but these adhesives tend to fail with time.
* When using dyed or synthetic fabrics, always isolate your objects from exhibit fabric with polyester film, such as Mylar® or Melinex®. 
== Additional Resources ==
* Stephens, C. H., N. Britton, I. Buscarino, L. E. Peluso, J. Carlson, L. Rosa, and E. M. Breitung. Washing cotton fabrics for use with collections, AIC News 44: 1,6-12.
* Grzywacz, C. M. 2006. Monitoring for gaseous pollutants in museum environments. Getty Publications. Los Angeles.
* Thickett, D. and L. R. Lee. 2004. Selection of materials for the storage or display of museum objects, Occasional Paper The British Museum 111: 1–30 .
* Puls, J., and S. A. Wilson, Degradation of Cellulose Acetate-Based Materials: A Review Journal of Polymers and the Environment 19: 152-165.
* Ballany, J., D. Littlejohn, R. A. Pethrick, and A. Quye. 2001. Probing the Factors That Control Degradation in museum collections of cellulose acetate artefacts, in Historic Textiles, Papers, and Polymers in Museums, 145–165. Washington, DC: American Chemical Society.
* Stephens, C. H. and E. M. Breitung. 2021. "Impact of volatile organic compounds (VOCs) acrylic double-sided pressure-sensitive adhesives (PSAs) on metals found in cultural heritage environments." Polymer Degradation and Stability 193.
* Hatchfield, P. 2004. Pollutants in the Museum Environment : Practical Strategies for Problem Solving in Design, Exhibition and Storage. WAAC Newsletter 26: 1-22.
* Timar-Balazsy, A. and D. Eastop. 2004. Chemical principles of textile conservation. Butterworth-Heinemann. Oxford.
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