Re: drying twist test in fibre identification

[Joan Marshall <joanmarshall@xxxxxxxxxxxxxx>]

Jennifer,

This test is ancient history for me, but I can tell you that I had consistent success with it.  It's all in the precision of the methodology.  One of the most important things to do is to glue a tiny piece of square paper to the end of the fibre.  this magnifies the movement and makes it unmistakable.  The more degraded the fibre, the less likely it will be to react (for obvious reasons).  And it does matter which direction you view the fibre.

Let me know if you need more precise directions.  The sources Vivian cited from my thesis had good information.  Can't remember how much I streamlined the methods.  I can send more information directly to you on the weekend, if necessary.

Good luck,

Joan Marshall

On 26-Feb-07, at 5:12 PM, Jennifer BARNETT wrote:

Dear colleagues,

Today a group of students and I went about carrying out the drying twist test on linen and hemp fibres, following the method described in "Identification of textile fibres", The Textile Institute, 1985, 7th edition

Make a fibre thoroughly wet then remove excess water with a tissue. Grasp one end with the tweezers and hold the free end over the heat source (in this case, a hot plate). Observe the movement of the fibre by pointing the free end directly towards you. 

results

• clockwise

- linen, ramie and nettle

• anticlockwise

- hemp and most other fibres

• alternating clockwise and anticlockwise

- cotton

Our results: two different linen samples repeatedly twisted anti-clockwise while the one hemp sample (identified by the Neocarmine W stain test) twisted clockwise. Cotton performed as to be expected. So many contrary reactions (particularly with the linen) would seem to cause doubts as to the accuracy of the described expected result. Could this book possibly be wrong? Could there be other factors at play? Any other thoughts?

Not having any other references to hand in which this method is mentioned, I hope someone has another source for this test to check the expected direction of twist for linen and hemp.

With thanks,

Jennifer Barnett

Regina Textilia

historic textiles conservation, research and consultancy

Route de Dancé

FR - 42260 Bully

tel/fax * 33 (0)4 77 65 20 11

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