This shocking pink-and-orange-striped fabric sample (Fig. 1) was designed by Dorothy Liebes presumably for Jasco Fabrics, but it also showcases the innovations of another client: DuPont. The fabric incorporates natural wool and synthetic acrylic and nylon fibers, but the casual observer might not be able to distinguish between them, and that is intentional. As a consultant to DuPont’s Textile Fibers Department, Liebes experimented with the department’s newly developed fibers and proposed changes to make the yarns more functional or interesting from the textile designer’s perspective. The manufacturers, in turn, manipulated the physical characteristics of the synthetic fibers to mimic the qualities of wool or other natural fibers. Only through magnification and analysis do the differences become clear.
Janet Lee, contract textile conservator, and Kira Eng-Wilmot, Cooper Hewitt’s textile conservator, analyzed and identified the fiber and plastic materials used in the Dorothy Liebes textiles in Cooper Hewitt’s collection. Polarized light microscopy techniques using an Olympus BX50 microscope and Fourier Transform Infra-red Attenuated Total Reflection (FTIR-ATR) spectroscopy with a Nicolet iS5 with OMNIC™ software were particularly useful in identifying the fibers found in this and other Liebes textile samples. As a consultant, Liebes had privileged access to novel fibers being invented by DuPont, so any less common synthetic fibers found in the group were prime candidates for in-depth research.
The weave alternates a fine orange warp with a bulkier bright-pink one. The orange warp is wool: under polarizing light microscopy, the tell-tale scale pattern and darker central core structure, known as a medulla, are visible (Fig. 2).
The pink warp and weft are acrylic, probably DuPont’s Orlon, the first mass-produced acrylic fiber. Both fibers have a distinct dog-bone shape under plane-polarized light microscopy (Fig. 3) and, under cross polars with the first order retardation 530 nanometer plate, demonstrate the distinct optical qualities of these birefringent fibers (Fig. 4). With fiber parallel to slow direction of first-order Red plate, the interference colors are yellow-orange; with fiber perpendicular to slow direction of first-order Red plate, interference colors are blue. Dark particles on the surface may indicate a delustrant, a substance used to dull the shine of a synthetic fiber. A comparison of period reference samples with FTIR analysis and written period descriptions shows a very strong correlation with Orlon acrylic (Fig. 5).
The purple and orange wefts were identified as nylon, though they differ slightly. Under the bright field and cross section, the purple fiber has a trilobal shape, with one lobe distinctly darker than the others and a surface textured with parallel scribed lines (Figs. 6, 7). The orange weft is also a trilobal shape but is smaller, with a smooth surface and some pitting. After comparing these with period reference samples via FTIR analysis and written period descriptions, we believe these to be different versions of DuPont’s Antron, one of the company’s nylon 6,6 products (Fig. 8).
The analysis of this sample was part of a larger project undertaken to assess condition, perform materials analysis, and improve archival housing of the nearly 200 Dorothy Liebes textiles in Cooper Hewitt’s collection. Synthetics have been under-researched in the past, and Liebes’s role as a known materials innovator during a period that saw an explosion of new textile fibers, dyes, and finishes provided a unique opportunity to study synthetic and plastic materials used in weaving. This project received federal support from the Smithsonian Collections Care and Preservation Fund, administered by the National Collections Program and the Smithsonian Collections Advisory Committee.
Dembeck, Adeline A. Guidebook to Man-Made Textile Fibers and Textured Yarns of the World. 2nd ed. New York: The United Piece Dye Works, 1964.