Basketry

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Copyright: 2011. The Objects Group Wiki pages are a publication of the Objects Specialty Group of the American Institute for Conservation of Historic and Artistic Works. The Objects Group Wiki pages are published for the members of the Objects Specialty Group. Publication does not endorse or recommend any treatments, methods, or techniques described herein. 
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Broadly speaking, a basket is an object made of interwoven elements that is created without the aid of any device (like a frame or a loom) to tension those elements (Adovasio 1977; Rossbach 1973). Baskets can serve a variety of functions – they can be containers, mats, sieves, fish traps, hats, footwear, boats, architecture, furniture, toys, and so on.
Although basketry predates the weaving of cloth, they share the same basic techniques (Harvey 1986). Consequently, it can sometimes be difficult to categorize something – is it a basket or is it a textile? Objects do not always fall neatly into one classification, but a few points can help differentiate them: while textile arts make use of continuous, flexible, sometimes preassembled materials (plied thread, for example), basketry employs shorter and coarser materials which are progressively added as the basket is built. In addition, baskets can define spatial volumes without any additional processing. This is not true of cloth – an inherently planar entity.
==Materials and technology==
===Materials===
Baskets can be made from any number of different materials, natural or manmade. Depending on the material and the desired properties of the basket, certain processing steps may be required, such as boiling, soaking, smashing, shredding, retting, splitting, peeling, dying, drying, scraping, or bundling. However, “qualities are modified and enhanced, not through reforming or reintegrating the individual fibers as in yarn construction, but through the preparation of the materials…the constructions which exist in nature are retained, but reduced in size” (Rossbach 1973). An incomplete listing of commonly used materials, and a few examples of each, follows:
:::•	Monocot leaves (raffia palm, pandanas, abaca, sisal)
:::•	Monocot stems (bamboo, rattan)
:::•	Herbaceous dicot stems (flax, stinging nettle, hemp)
:::•	Tree barks (birch bark, spruce bark)
:::•	Wood splints (elm, ash, oak, cedar, willow, redbud)
::: •	Stems, rhizomes and roots (spruce root, birch root, bulrush) 
:::•	Hair, wool and fur
:::•	Rawhide, sinew, and leather 
:::•	Plied cordage
:::•	Plastic
:::•	Wire
Apart from the materials used to create a basket’s structure, countless others can be used to alter the appearance or performance of the basket. For instance, feathers, quills, fur, beads, shell, horn, dyes, ivory, etc. are added for decorative effect. A basket’s function may require that it be waterproofed with lacquer, shellac, clay, or pine pitch.
=====Definitions and parts of a basket=====
A few definitions will make discussion about techniques easier. Baskets are described as being made with elements. Elements can be passive ( those that form the basket’s structure without a having connective function; elements that do not move) or active (those that create coherency in the basketry structure; those that move). Depending on the technique, these elements can also be referred to with the terms warp and weft, spokes (or stakes) and strands, and foundation and stitch (or binder). Warp, spoke, stake, and foundation refer to passive elements, and weft, strand, stitch and binder refer to active elements.
A basket is worked from a center (also called a start or a beginning). Other starts are plaited or woven, are formed by the intersection of passive elements, or are formed by solid pieces of wood. The active elements (also referred to as the weft) are worked around the passive elements to support the structure. Walls or sides are the parts of the basket that rise vertically from the base. The rim or selvedge is the edge finish on the basket. In some cases, baskets may also have lids, handles and/or feet. These can either be integral to the structure of the basket, or can be added after the body of the basket is already complete.
===Technology===
Interworking techniques can be said to fall into just a handful of categories, but countless variations of each are possible and make a basket weaver’s repertoire a rich one. There are several resources that beautifully illustrate the many iterations of the main techniques: coiling, twining, and weaving/plaiting (Rossbach 1973; Adovasio 1977; Harvey 1986; Florian, Kronkright and Norton 1990; Wendrich 1991; NMAI 2003). Therefore only the basic techniques will be discussed here. It should also be mentioned that these techniques are not always used alone - subtle variations in pattern are achieved by combining techniques, by altering the number of elements that engage one another at once, by staggering those alterations, or even by changing the size of one of the sets of elements. Possibilities are truly endless.
=====Coiling=====
Coiled baskets can be described as moving clockwise or counterclockwise as they work their way outwards from the center – this is usually described as considered from the inside of the basket. In coil built baskets, the active element is a single, vertical stitch. The passive element is either single or multiple long rods (in what is known as rod coiling), or a bundle of separate, possibly shorter fibers (known as bundle coiling). The stitches wrap around the horizontally oriented foundation as it spirals outward and upward, holding the working end against the previous row. This creates the basket’s form and structure. As they wrap, the stitches can additionally interlock with stitches in previous rows, wrap around multiple rows, or be sewn through the foundation of previous rows for decorative effect.
=====Twining=====
Twining involves horizontal active elements that engage a series of vertical, passive warps. As they circle the basket, the wefts are separated and pass around opposite sides of one or more warp elements. They are then brought back together, and with a twist they effectively lock the warps in place. Most baskets are plain twining, and can be close or openwork. More complex twining includes triple-strand twining and twining in which the passive elements are also sometimes crossed (see image). 
center|500px|thumb|Photo by Rachel Freer-Waters, collection of Redwood National Park.
Wickerwork (or stake-and-strand basketry) is closely related to twining. It uses a single weft element and a series of passive warp elements that are typically much larger and stiffer than the weft element.
=====Plaiting and weaving=====
Plaited and woven baskets are made two or more active elements and no passive elements. Changing the number of elements can result in different patterning: two sets can give either plain weave (each element passes over one element, then under one element) or twill (each element passes over two or more elements, then under two or more elements), three sets lead to a hexagonal weave, and four make an octagonal overall pattern. 
Plaiting and weaving are distinguished by the angle at which the elements are interworked with respect to the selvedge – woven elements are placed parallel and perpendicular to the edge, while plaited elements occur at a 45-degree angle. 
=====Other constructions and decorative techniques=====
Of course, there are manifold ways that materials can be manipulated in the creation of basketry. Knotting can be used to join materials and for decorative effect. An entire basket made from knotting is very flexible and net-like. Linking and looping are done with a single active element that interconnects with itself. Wrapping is done by running a single element around and around a passive core, and is a common finishing technique for rims. 
There are several strictly non-structural techniques that merit mention as well. Imbrication, often seen on coiled basketry, is a method by which a supplementary flat strip is folded back and forth, each fold being couched down by a vertical stitch used in the coiling technique. The end effect is that of overlapping squares or rectangles. False embroidery is used primarily on twined baskets. In this technique a decorative strand runs alongside the structural weft elements but never passes through to the inside of the basket as the wefts do – it simply wraps around weft elements as they emerge on the outside of the basket’s wall.
===Identification===
300px|thumb|Sample of a stained cattail (Typha) stem cross-section, for materials identification. Photo by Rachel Freer-Waters taken with Image Pro-Plus under reflected UV radiation, slide collection of Arizona State Museum.
Further identification of the materials employed in a basketry object can be undertaken. The literature available on the topic is very developed and, together with a few simple pieces of equipment, positive identification may be possible (Florian, Kronkright, and Norton 1990).
Examination of the epidermis of plant-derived basketry fibers in situ can be helpful if the materials were not drastically altered by their preparation. Similarly, scale patterns on animal hairs are often recognizable.
Polarized light microscopy can be used to examine transverse (cross-sectioned) or longitudinal samples taken from a basket element. Cellular structures of basketry materials are distinguishable from one another under magnification, and chemical properties of the materials can be highlighted by the use of various stains. Stains make it possible to detect the presence of starches, tannins, fats, and proteins, helping a researcher narrow down the possibilities. Further analytical techniques can be used to identify dyes and coatings found on basketry.
===Deterioration===
Baskets made of organic materials are susceptible to many different types of degradation: physical, chemical, biological and mechanical. Photodegradation (caused by electromagnetic radiation in the visible and ultraviolet regions of the spectrum) causes embrittlement and fading. Relative humidity (RH) extremes are also of major concern. One reason is because plant-derived materials swell in high RH conditions and shrink in low RH conditions. Continual cycling between the two can cause damage to the cellular structure of individual fibers, eventually leading to permanent deformation. Excessive moisture can also encourage the growth of molds, bacteria and fungi. Plant materials are quite attractive to pests, as well. Rodents and insects can wreak havoc by consuming basketry elements and leaving behind frass and casings. Dust that has settled onto a basket’s surface exacerbates this problem. Finally, careless handling of baskets, especially those already weakened by the above factors, can crush baskets or lead to loss. Baskets should always be cradled in both hands, and carrying them by their handles should be avoided. 
==Conservation and care==
 This information is intended to be used by conservators, museum professionals, and members of the public for educational purposes only. It is not designed to substitute for the consultation of a trained conservator. 
*To find a conservator, please visit AIC's Find a Conservator page. 
===Documentation===
Several scholars have attempted to create an organized system of recording to accurately and meaningfully describe basketry (Adovasio 1977; Wendrich 1991). The forms they provide for this purpose are incredibly useful in guiding one’s attention to different aspects of a particular object, but may be more technical than necessary in some contexts. It is often sufficient to note a few basic details, including, but not limited to: 
:::•	Which basic weave structure is used?
:::•	What materials are used for the elements?
:::•	How are the elements spaced?
:::•	How many elements are engaged at a time?
:::•	How are insertions made when an element is exhausted?
:::•	What is the facing system? Is the basket warp faced or weft faced?
::: •	Is the stitch or wrapping slant S or Z?
:::•	Are there coatings, varnishes, or painted decoration on the surface?
:::•	Are there any signs of either indigenous or post-collection repair?
=== Preventive conservation===
Baskets should be kept in a stable environment, preferably between 40 and 60% RH and below 25 degrees Celsius (CCI Notes 1988). While it is important to protect basketry from dust and light, any covering must allow for circulation of air so as not to promote mold growth. When being stored or displayed, a basket’s structure should be adequately supported, and not compressed. This can be done with simple storage mounts, and with acid-free tissue stuffing can protect the interior from dust. Overstuffing a basket with the intention of supporting the walls can have adverse effects by outwardly stressing the inherent support structure of the weaving. Whenever possible, basketry should not be stacked for the same reason they should not be overstuffed. Abrasion to the interior active, or weft, elements can easily result in loss. A variety of creative solutions for storage can be found in the literature (CCI Notes 1988; Clark 1988; Florian, Kronkright, and Norton 1990; Clark 1993).
Important note: until the middle of the 20th century, it was common for many natural history and anthropology collections to be treated wholesale with organic and heavy metal pesticides. Unfortunately, these chemicals are highly persistent and quite toxic for humans. If you are unsure of the history of your collection, please use caution when handling such materials.
===Interventive treatments===
As with any other type of object, each basket must be considered unique in its conservation needs. Care must be taken to identify any culturally significant deposits so that they not be inadvertently removed along with post-collection alterations. What follows are brief descriptions of common solutions to the most frequently encountered problems, and should not be taken as prescriptions for treatment (more detailed discussion of specific treatments can be found in the references at the bottom of the page). It is recommended that any treatment be undertaken by a trained conservation professional.
====Cleaning====
Cleaning is done mechanically if at all possible. The preferred method is vacuuming under low suction while gently brushing dirt and debris loose with a soft-bristled brush. Often, the end of the vacuum hose is reduced in size and covered with fine netting to prevent loss of material and it never actually makes contact with the basket. Foamed latex rubber sponges are also helpful in removing stubborn soiling when gently rolled (not dragged) over soiled surfaces.
Although aqueous and non-aqueous solvent systems are also used, moisture introduced during a cleaning process can weaken or discolor component materials or cause surface soiling to migrate further into the fibers of a basket, so this should always be done with caution. The particular solvent used depends upon both the characteristics of the plant fibers from which the basket is made, and on the nature of the foreign material being removed. In general, local application of as little solvent as possible is advised, and this only after testing the solvent’s effects on an inconspicuous area.
==== Structural treatments====
Breaks or losses to a basket can be more than just unsightly – loose elements can snag during handling and lead to further damage. Extensive losses can also compromise the strength of a structure and make it unable to bear its own weight. Various tactics for stabilizing damage to basketry range from purely mechanical repairs (sewing or splinting, for example) to methods that rely on adhesives. Fills can be made with plant materials, paper, thread, cloth, wood, etc. They should be removable, but strong enough to provide support for a damaged area. Kronkright (Florian, Kronkright, and Norton 1990, 287-292) has written about using twisted and folded strands of mulberry paper adhered with starch paste to reconstruct lost areas of a basket. Alarcon et al. (Alarcon, O'Hern, and Pearlstein 2012, 123-143) have written about using Tyvek and dental floss as basketry repair materials. Native repairs are common with basketry collections, and should be considered as a permanent component of the basket when identified as such.
Over time, environmental and physical stresses placed on baskets can cause distortions. Depending on how extensive the damage and how structurally sound the component materials, baskets can sometimes be restored to their original shape. This is almost always achieved with gentle, controlled humidification to increase flexibility, followed by the use of wadding or weights to hold the basket in the correct shape until all introduced humidity has been dissipated. For severe distortions or very brittle plant fibers, it is often good to accomplish reshaping in stages.
====Other treatments====
Baskets found in archaeological contexts may present with additional difficulties – they might be carbonized or waterlogged, for instance – and require more complex treatments such as consolidation or deacidification. See the references below for several papers dealing with treatment of these types of materials.
==References==
 Adovasio, J. M. 1977. Basketry technology: A guide to identification and analysis. Chicago: Aldine Publishing Company.
 Alarcón, Tessa De, Robin O'Hern, and Ellen Pearlstein. 2012. "Case Studies in Basketry Repair: Two Abenaki Splint Baskets." Journal of the American Institute for Conservation 51(2):123-143.
Bernstein, Bruce, ed. 2003. The Language of Native American Baskets from the Weavers’ View. Smithsonian: The National Museum of the American Indian (NMAI).
CCI Notes. 1988. Care of basketry. CCI Notes 6(2).
 Clark, Thurid. 1988. Storage supports for a basket collection: A preventive conservation approach. Journal of the American Institute for Conservation 27(2): 87-99.
 Clark, Thurid. 1993. Storage supports for basket collections. NPS Conserve O Gram 5(1).
Florian, Mary-Lou E., Dale P. Kronkright, and R. E. Norton. 1990. The conservation of artifacts made from plant materials. Los Angeles: The Getty Conservation Institute.
 Harvey, Virginia I. 1986. The techniques of basketry. Seattle: University of Washington Press.
The National Museum of the American Indian (NMAI). 2003. The language of Native American baskets from the weavers’ view.
 
 Rossbach, Ed. 1973. Baskets as textile art. New York: Van Nostrand Reinhold Company.
 Wendrich, Willemina. 1991. Who is afraid of basketry. A guide to recording basketry and cordage for archaeologists and ethnographers. Leiden: Center of Non-Western Studies, Leiden University.
==Further reading==
Agua Caliente Cultural Museum. 2006. Western Science Seeks Cultural Knowledge
Alaska State Museum. 2000. Conservation wise guide.
The Burke Museum of Natural History and Culture. Re-discovering ancient basketry from the Biderbost site.
Carrlee, Ellen. Blog. Ellen Carrlee Conservation.
Fields, Virginia M. 1985. The weaving process in the Hoover collection of Karuk baskets. Eureka, California: The Clarke Memorial Museum. 
The Langley Centennial Museum. First Nations baskets at the Langley Centennial Museum.
Paterakis, Antonio. 1996. Conservation of a Late Minoan basket from Crete. Studies in Conservation 41(3): 179-182.
Rinne, Melissa M., Koichiro Okada, Kaz Tsuruta, and Robert T. Coffland. 2007. Masters of bamboo. San Francisco: Asian Art Museum.
Schaffer, Erika. 1976. The preservation and restoration of Canadian ethnographic basketry. Studies in Conservation 21: 129-133.
Senge, Dana. Blog. Waterlogged basketry.
Sentence, Bryan. 2001. Art of the basket: Traditional basketry from around the world. London: Thames & Hudson.
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