Salt vs. Vinegar to fix dye

topic posted Wed, April 9, 2008 - 10:49 AM by  Kimberley - ...
I originally posted this on Crafty Vixens and some said I might try here. . . .

I just returned from a trip to India last week. While I was there I purchased about 15 meters of raw silk (in beautiful reds and blues). I was told I need to fix the dye on the fabric with salt when I returned home. I've not used salt to fix dye before so I don't know how to do this. . . .

Typically when I dye, it's nylon and I fix the dye with vinegar. . . . . .what is the difference between salt vs. vinegar?

I don't want to ruin the beautiful silks I just bought . . . . . . .Advice please
posted by:
Kimberley - M.o.E.
SF Bay Area
  • Unsu...
    salt is a tried and true way. But it depends on the color. Search "color appropriate mordant" on google. That should get you a bunch of answers. I use salt in my rit dye, but that is what rit calls for.
    • Unsu...
      Both are 'Mordants' an agent used to help the dye pigment.
      Different ones can also affect the color somewhat.

      One word of caution - Silk can be harmed by long term exposure to acids, and esp. salt. Be sure you rinse after fixing it with a neutral ph bath. Can be made by adding a bit of soda or whatever you use. If you're really worried, get some PH test paper and check it.
      • silk is harmed by long term exposure to alkaline, not acid. using soda ash can irreperably damage silk, but acid dyes do no damage to the silk and dye it beautifully.
        • Unsu...
          Sorry, guess I was thinking of the old metal salts. I actually dyed and wove silk professionialy so i have no excuse (lol). Maybe we should talk about the long term effects on the brain ;-)
  • Vinegar can darken a bright red to a burgundy (we learned the hard way on a friend's red and white sari) so be careful, always test a small place with either the salt or the vinegar. Make sure to let the test spot dry to see what the real result is. The reds and blues may still run even after you have set them, like you will see you have red finger tips after wear them, or blue armpits if you make a choli out of it, but there is just not much you can do about it other that setting a running hose over the material and letting it run for hours (we tried that once and still maroon was running out of a dark dupatta).
  • In my experience, silk also responds to heat and steam. If the silk has no metallic embroidery (or it is all silk), having the dry cleaners steam it can also be an alternative.
    • I've steamed silk before and second this suggestion, though if you want to do it at home, it takes some setting up. has free information on how to make your own steamer (Ignore the uber expensive professional steamer you can buy). My only concern about having the dry cleaners steam it is would they steam it for long enough? The dyes I worked with said they needed to be steamed for at least and hour and up to three.
  • If really want an accurate answer then you need to sacrifice some of the yardage and make test swatches and treat them to find out which would work best.

    In dyeing, salt is not a fixative. It helps to make the dye release from the solution and make it more available for the fabric. Salt is usually recommended for synthetic dyes being applied to plant fibers (cottons, rayons, linens, hemp, etc.). Vinegar is only useful in the presence of acid dyes and protein fibers (silk, wool, camel, alpaca, etc.) and heat. When a vinegar solution is heated slowly with protein fibers, it bathes the fabric in an acidic solution thereby allowing the acid dyes to deposit readily in the fibers.

    You can get a dye fixative like Retayne. It is a true fixative. You absolutely must test a swatch to see the actually final product.

    Personally, these types of fabrics that I would like to maintain in original condition, I would only design clothing that would never require washing or ever be exposed to sweat/ salts/ moisture/heat. So I would consider making only skirts, scarves, shawls & sari with them. Never a choli.
  • Unsu...
    i recently tried to set the dye in my black (cotton) jaipur skirt with vinegar but it didnt seem to help much. i still get dye all over my hands when i put it on. would salt be a better choice? how much do i use? any help is greatly appreciated.

    : )

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