Setting the color in dyed fabric

[Lady Renee Buchanan]

My husband's yellow ren shirt has faded, so I bought some Rit dye.  I know people have said that you set the color of a dyed item by using vinegar, but I haven't figured out how to do it.

Is it plain white vinegar?  Do you put it in the water with the dye & the shirt, or do you rinse the shirt and then put it in the vinegar?  Mixed with water?  Hot water, cold water, tepid? 

I really need instruction on dyeing for dummies.  If someone can tell me the process step by step, I would really appreciate it.  Thank you.

[isabelladangelo]

For RIT, I use salt in the washing machine with the dye.   It works well!

[DonaCatalina]

For any dyes, I use salt and calsolene oil which I get from Dharma trading. But for a relatively lihgt color like yellow, just salt should be sufficient. I use white vinegar to remove stains on fabric that can't be bleached.