Fiber identification is one of the most important—and arguably one of the most difficult—analyses in the world of textiles. Fiber content can determine import duties, care instructions, price point, and product performance.
And sometimes, the best way to identify a fiber is by its cross-section (the end-view). With a few simple supplies, you can view fiber cross-sections and compare them to known fibers in American Association of Textile Chemists and Colorists (AATCC)Test Method (TM) 20, Fiber Analysis, Qualitative1 or your own fiber library. Of course, both creating useful cross-sections, and using them to identify fibers, take plenty of practice.
Plate Method
TM20 offers two basic methods for cross-section preparation. The first uses a cross-sectioning plate. Fibers are inserted through small holes and trimmed flush with the plate.
The test method mentions a stainless steel plate and copper wire, but a plastic plate and a needle threader (see photo, right) work just as well.
Embedded Method
In the second method, an “embedded” cross-section is created by applying collodion to a bundle of fibers. Collodion is nitrocellulose in alcohol and ethyl ether that creates a sticky film around the fiber bundle, making it easier to handle and slice (think bugs trapped in amber).
For a simplified version of this method, a small cork can take the place of the collodion. Fibers are pulled through the cork using a sewing needle. Slices of the cork are placed on a microscope slide for examination.
Filler Yarn
You only need a few short fibers for microscopic analysis, but that may not be enough to fill a hole in the cross-section plate or thread through a needle. To do these things, you may need a “filler” or “carrier” yarn. The yarn is used to pull the fibers through the plate or the cork.
Since the filler fibers will appear in the cross-section along with your other fibers, it's a good idea for the two to be as different as possible. Choose a filler color that contrasts with the color of the fibers you want to examine. The AATCC microscopy kit includes both black and white yarns for this purpose. Ideally, the fiber shapes should be different as well. AATCC filler yarns have a distinctive triangular cross-section that will not be confused with most other fibers.
American Association of Textile Chemists and Colorists (AATCC)
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