Hi - Barbara Anne - you said and asked:
A light bulb went off in my mind. For years I have made pysanky (ukranian easter eggs) and always added vinegar to the dyes. I am not familiar with RETAYNE or SYNTHROPOL, thanks Margo, for the links to learn about these products. I am curious to know if vinegar is part of their formula, but doubt that this information is available to the public. Is there any information of the packaging indicating the contents? Does the type of dye dictate how to "permanently" set the color? Are there any chemists out there that can explain more about the use of vinegar as a setting agent?
My husband is a chemist. He is going to look into this particular issue and see what he can find out for us. YAY..... He says that this particular field of chemistry is a specialty field of it's own. There are many types of dyes - some are organic (plants, vegetable, animal, bugs - Yes - it is true

) and many synthetic - and one single type of product will not address the bleed-out of every single type of dye. Vinegar is acidic acid. I have personally found it to be helpful in "setting" color in pre-washing fabrics, but it does not always stop the bleeding in all cases and you must rinse thoroughly to get out the vinegar odor. I've never tried RETAYNE or SYNTHROPOL, but will order some and try it.
That's all I can contribute right now. As soon as he gets some answers, I will reply.
Ruth (RUTABAGGY)
Just remembered something: I bought a hand-dyed batik pareo in Grenada & the lady in the shop told me to walk into the ocean while wearing it, as the sea water would "set" the dye. Now, I guess we can't all just walk down to a beach & rinse our fabrics and/or quilts. Maybe some components of sea water (fish pee??? eeekkk!!!) other than salt work some magic. But I think I'll mix up some salt water, put in some test fabric & see what happens.