[MR] Setting Dye With Vinegar

[Betty Eyer]

Like most old-wives tales, this one is based on fact,
but often improperly applied.  This is a case of
applying what is true in a narrow context to all
situations. 

One:  Some dyes are pH affected.  The color that you
want may be the one that needs acid; for instance
madder does a brick or cranberry to rose conversion
based on pH.  Thus the vinegar.  But even here, a pH
strip ought to be used first, because most of the tap
water in Atlantia is mildly acidic anyway. 

Two: wool, and to a lesser degree silk, does not like
alkaline.  Makes it sticky, unpleasant next to the
skin and brittle.  Worse case, it just falls apart. 
The soaps of 50-100 years ago were lye(alkaline). 
Thus the vinegar to counteract the alkaline after
rinsing out left over dyestuff with soap.

Three: The process by which indigo attaches to fibers
is a chemical reaction that frequently involves a base
waterbath.  Indigo that is loosely attached to the
fibers will continue to bond chemically as long as the
process continues.  So, theoritically, your blue could
get bluer than you wanted (I should be so lucky). 
Adding an acid will stop the reaction and thus "fix"
the blueness.  This is my favorite theory. 

Four: Modern chemical dyes have their own particular
chemistry.  Read the instructions on the dyestuff. 
Some of these say to add vinegar or salt.  If you are
adding vinegar to a modern chemical dye that does NOT
call for it you are at best making your clothes smell
funny and at worse may cause bad results or damage to
your fibers.


--- ThatUrsula at aol.com wrote:
> Greetings.
> 
> Someone once told me how to set fabric dye by
> soaking the dyed article in a 
> mixture of white vinegar and water, but I can't
> remember the particulars.
> 
> Does anyone tell me:
> 
> What's an effective vinegar-to-water ratio?
> Also, should the water be hot or cold?
> Finally, how long should it soak?
> 
> With thanks,
> Ursula
> 
> 
> 


=====
Magdalena de Hazebrouck-Purpure, a fess fusilly argent between three torches or. While Joshua was near Jericho, he raised his eyes and saw one who stood facing him, drawn sword in hand.  Joshua went up to him and asked "Are you one of us or of our enemies?" He replied, "Neither.  I am the captain of the host of the Lord and I have just arrived in this valley." Joshua 5, 13-14.

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