Washing silk

[ikarsten <ikarsten@xxxxxxxxxxxxxxxxxxxxxxxx>]

I have recently washed several metres of silk fabric in preparation for a 
research project.  I was quite amazed to see how many rinses were necessary 
before the detergent suds were removed.  The fabric was from Testfabrics, a 
silk habutae (#609), which is a light-weight, plain weave fabric.  The fabric 
had been desized, scoured and degummed before shipping to me.  I hand washed 
the fabric using Orvus WA Paste at a concentration of 3 grams/litre (the cmc 
of Orvus in the water that we use as measured by Rebecca Tinkham).  I first 
washed the silk using reverse osmosis purified water and standard conservation 
techniques identical to those I had used for silk crepeline and polyester 
crepeline, with three intial baths, including the detergent bath, at 40C. 
After 17 rinses, including a few with running water, considerable bubbling, 
presumably from the detergent, was still being released.  I then washed the 
silk in tap water, which enabled me to wash and rinse at higher temperatures 
(55-60C), with similar results.  Twenty rinses, half in tap water, half in 
purified water, were necessary to remove the detergent residue.

I also washed a similar, plain-weave nylon fabric in hot tap water, as I had 
the silk, and found that the fabric had rinsed clear in 6 rinses.

Has anyone observed similar results for washing silk?  Is the fabric 
construction an important factor in detergent retention (the silk crepeline 
rinsed out okay)?  What cleaning procedures have you used for preparing silk 
fabrics for backing purposes, or do you generally avoid silk?

I am aware, from the research done by Rhee and Ballard (ICOM-CC 10th Triennial 
Meeting Washington, 1993, Vol. 1, 327-329), that anionic detergents are highly 
attracted to silk fibres.  I understood from that article, however, that 
rinsing was very effective in removing the detergent.  How little residue is 
sufficient to produce bubbling in the rinse water?

Thanks for any observations and feedback.

Irene Karsten

Doctoral Student in Textile Conservation
Department of Human Ecology
3-02 Human Ecology Building
University of Alberta
Edmonton, Alberta
Canada  T6G 2N1

Phone: 780-492-5385
Fax: 780-492-4821
E-mail: ikarsten@xxxxxxxxxxx