Re: prespiration- stains on silk

["Mary W. Ballard" <BallardM@xxxxxxxxxxxx>]

Apologies for a very slow response. 
1)The combination of salts and acid from perspiration damages silk (because the fiber diameter is so small, the fiber is thinner & by weight less to destroy?) and the dyestuff. 
2) In the US there is a "standard test" by the textile industry for colorfastness to perspiration. The composition of perspiration (in the standard) is: deionized water, sodium chloride, lactic acid, disodium hydrogen phosphate,  and a little l-histidine monohydrochloride. The final pH is 4.3; fungi begins to grow in acid perspiration and raises the pH. The solution is not viable for testing after 3 days.
3) Very dilute lactic acid mixed with a little surfactant works well for tannin stains but for myself, I have had more success with alkaline or enzymatic based reagents for perpsiration stains, perhaps because  the actual residue is altered by biodeterioration, by oxidation, or by anti-perspirant formulations. Alkaline or enzymatic based reagents have worked for me on heavy, cellulosic textiles--cotton machine lace wedding dress, etc. even after 30-40 years.
4) It is likely that the silk fiber is damaged--much like the acid rinses on 19th century silks--although the coloration dye might be somewhat reversible. 
If you/any one else would like a copy of the test method and composition, please send your name and mailing address to me, privately by emailing me at ballardm@xxxxxxxxxxxx  Sincerely yours, Mary Ballard

>>> ALang.RES.SPA.DHM@xxxxxxxxxxx 07/27/01 05:33AM >>>
Dear colleagues,

I'm verry glad to have learned about this list from one of my 
colleagues in Berlin.
My name is Andrea Lang and I'm working at the Deutsches 
Historisches Museum as an textile conservator.
I have a problem with prespiration stains in a lady's dress from 
the end of 19th century. It is completely made from silk. 
The prespiration has damaged the fibers in the ground fibric and 
in the lining, in the area below the arms. The fibers and the textile 
are broken, somewhere the fragments are broken out. The dye 
of the ground fibric are partial changed from brown to red and 
dark brown.

What happens? Which substance, contains prespiration, 
damaged the fibres? I took the ph, it is between 5 and 6, not a 
problem for silk, I think. Salts also contained. So the fiber will 
recept the humidity in the area of stains more than in the areas 
around it. This can result in stress and areas of weakness at the 
edge of the stains.
Now  the dress will undergo a conservation treatment because it 
will go into an exibition. Therefore a part of the arm seams have 
to be separate.This is the chance to remove the harmful 
substances. Do I have to remove it? 
Is there anyone who can help me with the cemical problem/ 
understanding? 
And is there anyone with  practical experience in removing stains 
from historical textiles? Is it possible, to remove without 
enlarging the area of the stain in silk?
On the other hand we have optimal climate conditions for our 
exebits in both, the storage areas as well as in the exebition. 

I woud be verry glad to get an answer,
Thanks,
Andrea Lang
Textilrestauratorin 
Deutsches Historisches Museum