Textiles and Their Structures

By Ann Coppinger

We cannot control the fact that organic materials deteriorate, but we can slow the process. An excellent way to understand the causes and ways in which you can control deterioration is to study the nature of the object or textile.

For the most part, historic textile collections are made from organic materials. The first synthetic manufactured fiber was Nylon, which dates to approximately 1939. All other textile materials prior to that are from either natural sources or beginning in the late Nineteenth Century are from regenerated materials. In lay terms this means natural materials reformed with the addition of chemicals.

The smallest element of a textile is the fiber itself. They can be a finite length (staple) or a seemingly infinite length (filament). Most fibers are spun or twisted together to form a long, continuous strand called a yarn. An exception is felted textiles, whereby fibers are joined in the presence of heat, moisture and agitation to form a mat-like textile usually made from wool. Yarns can be used as singled strands or plied with another yarn to give it increased strength or dimensional uniformity. The yarns are then woven or knitted into whole cloth or purposefully shaped based on the final intended cloth object.

Textiles can be colored or decorated with the application of dyes, pigments and special finishes. Textiles can also be embellished with embroidered stitches, beads or sequins, as well as metallic elements. Textiles can be dyed at the fiber, yarn or whole cloth stages. Dyes chemically unite with the textile while pigments simply sit on top of the textile substrate. Textile finishes can be achieved by either mechanical or chemical processing. All of this processing and the added features serve to make the care of textiles a sometimes precarious situation.

Natural fibers can be divided into two distinct groups, those that come from animals and those that are plant based. Cotton and linen (generally referred to as flax in its fiber form) come from plants and are composed mainly of cellulose. Silk and wool (for the sake of simplicity, I will use this term to refer to all animal hair) are from animals and are composed of proteins. All of these fibers, in their natural state, need water or moisture to grow and survive. Their physical structure is such that it is conducive to transporting moisture for survival.

That's the good news when they are part of living organisms. This continues to be a positive attribute when fibers are turned into utilitarian textile objects. Most natural textiles are valued for their ability to absorb liquids, feel comfortable against the skin and retain warmth.

However, when textiles enter museum collections they are no longer used except for study as objects that tell a story. More than likely, they are compromised and weakened from their previous owner's care and use. That once positive attribute now becomes an inherent vice, making textiles one of the more fragile objects a museum can have in its collection. Textile fibers will still retain their ability to absorb and lose moisture. Therefore textile objects respond to humidity fluctuations in their environment, causing slight physical movements to the fibers as they take in and release moisture. Constant expansion and compression within the fiber's structure serves to severely weaken the textile overall. This is one of the primary reasons a stable environment is critical to good textile care.

Textile fibers are spun together to make long, continuous strands called yarns. Fibers that are spun in a counterclockwise rotation are said to have a Z twist or right twist, the most common. Yarns that are spun in a clockwise direction have an S twist or left twist. Fibers can be spun by either rolling the fibers down the spinner's thigh, using a spindle, using a spinning wheel, or by mechanized spinning equipment.

Yarns are woven, knitted, plaited or knotted to form various textile structures. The most common structure is created by weaving, defined as the interlacing of warp and weft yarns on a loom. There are three basic weave structures; plain, twill and satin. All woven textiles are made using one or more variations of these weaves.

Textiles are then decorated by dyeing, finishing and/or various applied elements. All of these factors serve to compound the nature of the textile. For example, an embroidered sampler may consist of a linen ground cloth that has been embroidered with silk threads. The textile is composed of both cellulosic (linen) and protenaceous (silk) materials. The linen may not have been dyed, but the colored silk threads would have been. Depending on the dye, the silk threads will deteriorate at different rates; generally the browns will go first. And to further complicate the situation, the inks used to draw the patterning on the linen also add to the degradation process.

Textiles go through a great deal of processing from their raw state to the finished, utilitarian product. They are then used and cared for by their owners. All of these factors contribute to the history of the object and its eventual destruction. So hopefully at this point it has become a bit clearer why they should be handled with extraordinary care when they are part of a collection.

Excerpt from MS212: Care of Textiles beginning May 4, 2015.

Ann Coppinger runs the conservation department and teaches conservation at the Fashion Institute of Technology in New York. She has a master's in museum studies specializing in costume and textile conservation from FIT. She is a former NEA master apprentice at the Textile Conservation Workshop. Ms. Coppinger previously worked for 22 years in fashion in New York City. She has degrees in both fashion design and pattern making from FIT. 

The Field Lab

By Diana Komejan

Activities in the field lab

Think about your typical archaeological site. The vast majority of archaeologists work in primitive conditions. The same is true of most field conservation labs. As a result, identifying, registering, packing and performing simple treatments are the most you can hope to accomplish in a field lab.

Cleaning should be minimal. Limit activities to soft brushing to remove loose dirt, possibly with gentle encouragement from a bamboo skewer or wood applicator stick. If more cleaning is required, then you should have a conservator staffing the field lab.

Registration assigns a number to each find. This number ties the paperwork - the records you create - to the find. Usually the site registrar is responsible for primary record keeping.

Record keeping requires that you tell as much as possible about the piece in the field. It's also important to include condition photographs and simple condition reports - something a conservator might complete. In the records, also note pieces that could benefit from X-rays. The conservator ensures condition and treatment records are linked to the registrar's records using appropriate site numbers.

Drying. You may be able to dry some artifacts, such as certain stable ceramics or glass. Always test dry a sample artifact to make sure no changes occur. Metals, from "dry" sites should be air-dried before packing and kept dry in sealed boxes with dry silica gel. Antler and bone from dry sites can usually be air-dried, too. However, the unheated site lab humidity may still be much higher than the storage area that is centrally heated. Taking material from the field to storage can be problematic. Organic materials should go through a conservation facility first.

Packing. All artifacts should be packed for safe shipment back to the research facility. Further examination and conservation would occur there.

In some instances, there is no research facility or main laboratory where artifacts will receive further treatment. In those cases, your field lab must provide more in depth treatments, bringing the artifacts to a stable state for long-term preservation. This will require more staff, more time and more materials. Even then, some objects might be temporarily stabilized and stored for continued work in a following season.

Role of the Conservator

Large archaeological excavations where many artifacts will be found are best served by having a conservator on site. A conservator can identify materials, assess artifact conditions, and deal with potential site problems such as excavation of fragile artifacts using block lifts or separating layered materials, such as paintings on stone walls.

Conservators also can make decisions about long-term storage and treatment that will be of great assistance when the artifact gets back to the research facility. Conservators can do basic treatments and pack artifacts for transport.

If you do not have a conservator, assign one person to assess the condition of artifacts and to pack them for storage. That person also may be capable to perform basic conservation tasks such as simple cleaning and stabilizing. This person should have enough field expertise and common sense to know what is feasible and what is not. It's also important that this person work closely with the site registrar to develop a work plan that ensures smooth processing of artifacts.

For sites with a large amount of material, a triage may be necessary. Sort the finds by priority - some need immediate attention, some can be stored and worked on over the next few decades. Consider reburial as an option. If you are finding material that you are not equipped to handle, cover that area back up and return later when you have the expertise to excavate that material and care for it properly. Even on sites with a conservator, problem objects will be reburied, giving the conservator time to assemble supplies and develop a treatment approach.

Excerpt from MS 215: Care of Archaeological Artifacts from the Field to the Lab beginning May 4, 2015

Diana Komejan graduated from Sir Sandford Fleming Colleges Art Conservation Techniques program in 1980. She has worked for Parks Canada; Kelsey Museum, University of Michigan; Heritage Branch Yukon Territorial Government; National Gallery of Canada; Canadian Museum of Nature; Yukon Archives and the Antarctic Heritage Trust and is currently teaching Conservation Techniques in the Applied Museum Studies Program at Algonquin College in Ottawa. In 1995 she was accredited in Mixes Collection with The Canadian Association of Professional Conservators. Her work as a conservator has been quite broad in scope, having worked with historic sites, archaeological excavations and museums. In addition to lab treatments, Diana has broad archaeological experience, including the excavation of mammoths and dinosaur tracks.