18
Hemp fiber identification project
Robert C. Clarke
International Hemp Association
Since 1995, the
International Hemp Association (IHA) has solicited assistance from researchers
to establish protocols for the identification of Cannabis hemp fibers.
Our interest was first piqued in 1995, when we visited Dr. Elena Mikolaychuk at
the Hermitage Museum in St. Petersburg, Russia to view Cannabis remains
recovered in the late 1940s from a Scythian era (ca. 2400 BP) tomb near
Pazyryk (Rudenko 1970). Dr. Mikolaychuk showed us well-preserved Cannabis
seeds and some unidentified (possibly hempen) textiles and asked if we would
find experts to determine their fiber content. We agreed, and she provided the
IHA with three tiny samples taken from different parts of a nearly intact shirt
and a fourth sample from the sleeve portion of a second garment.
The identification of fibers in
textiles recovered from archeological contexts is often complicated by their
decomposition during burial. Although the Pazyryk remains were most likely
continually frozen in ice from soon after the time that they were entombed until
they were recovered, and are relatively well preserved, positive identification
has proven problematic. These samples have now been studied by both light and
scanning electron microscopists specializing in fiber identification and we hope
to present positive fiber identification of the Pazyryk textiles in the near
future.
Determinations of the hemp fiber
content of textiles is also required in other applications. Cultural artifacts
in museums are often classified by material type, but the identity of plant
fibers used in their construction is rarely recorded. Ethnobotanical researchers
working with museum collections require positive fiber identifications before
accessions can be included in research projects and publications. The largest
problem with positive determination of fiber content in cultural artifacts is
the wide choice of bast and leaf fibers that could possibly have been used to
make the artifact. Researchers investigating potentially hempen artifacts must
know whether they are working with Cannabis hemp. Determining whether an
artifact contains hemp fibers is quite a different matter than positively
identifying which other fibers it may contain. Accurate fiber identification
relies on comparisons of unknown samples with extensive collections of voucher
samples taken from botanical specimens. The IHA has assembled stem samples of
various bast fiber species collected in several locations and these samples will
be made available to qualified investigators.
Buyers and sellers of modern pure and
blended hemp textiles require accurate identification of hemp fiber content for
quality assurance. Few independent or government analytical laboratories will
perform textile fiber content analyses, and none specialize in bast fiber
analysis. Analyses by independent laboratories can be very costly, depending on
whether the results list only the presence or absence of hemp fibers, the
additional fibers are identified, and/or the percentages of the various fibers
are determined. Analysis costs are high largely because none of the independent
laboratories analyze only textile fibers and therefore each analysis bears the
cost of setting up the analysis protocol. A small laboratory dedicated to
vegetable fiber analysis should be able to perform analyses at a lower price.
The treatment of the textiles, such as dying, bleaching, softening or other
finishing techniques may also alter the appearance of the fibers and complicate
analyses. This problem is most evident in modern fabrics, but also occurs in
traditionally processed hand-made fabrics. The IHA has collected many swatches
of historical and contemporary hemp fabrics for use as a reference collection.
The Hemp Industries Association (HIA)
has worked for several years to establish an industry-wide certification program
for hemp textiles and garments. One of the major obstacles has been the lack of
affordable textile analysis by impartial laboratories. Most expertise in bast
fiber analysis resides in hemp producing nations such as China, Hungary, Poland
and Romania. Laboratories in these countries may have a vested interest in the
results of hemp textile analyses. Therefore, importers and wholesalers would
prefer to rely on a single laboratory located in a western nation that does not
produce hemp textiles.
Several sources give descriptions and
measurements of Cannabis hemp and other fibers. Mauersberger (1947)
reports fiber measurements, descriptions and chemical tests for many of the
fibers of commerce. Catling and Grayson (1982) provide detailed descriptions of
several vegetable fibers and in-depth comparisons of the anatomical fiber
features between several fiber species. Rahman and Sayed-Esfahani (1979) used a
scanning electron microscope to characterize the surface changes in hemp fibers
during various stages of processing. However, none of these researchers have
published any data for archeological specimens or samples of hemp textiles
processed by traditional methods. Ryder (1993) reported on the identification of
hemp fibers recovered from a Bronze Age site in Scotland, based mostly on fiber
diameter.
Dorothy Catling of the University of
Durham in England will teach a short course on vegetable fiber identification in
July and the IHA will finance a member to attend. We hope that the course will
lead to additional training to perfect the particular skills required for bast
fiber identification. The HIA can request this trainee to set up an official
hemp fiber certification program.
References
Catling, Dorothy and John Grayson 1982 Identification of Vegetable Fibers. Chapman and Hall, London and New York:18-23.
Clarke, R. C. 1995 Scythian Cannabis verification project. Journal of the International Hemp Association 2(2):104.
Mauersberger, Herbert R. (Ed.) 1947 Matthews’ Textile Fibers. 5th Ed.: John Wiley & Sons: New York:305-368.
Rahman, M. M. and M. H. Sayed-Esfahani 1979 Study of the surface characteristics of hemp fibres using scanning electron microscopy. Indian Journal of Textile Research 4:115-120.
Rudenko, Sergei I. 1970 Frozen Tombs of Siberia, the Pazyryk burials of iron age horsemen. Univ. of Calif. Press, Berkeley and Los Angeles:34-37, 62, 284-85.