I buy Retayne from Dharma.com. It is a color fixer, I use it when dyeing fabric. If you use it with your first wash of anything fabric, from fabric, to clothes, to quilts then the color will not bleed or migrate later. The large bottle is economic to buy. No need to buy anything that needs to be used over and over. By the way the washing soda solution really works. It makes a molecular bond between the natural fiber and the dye. It does not work with synthetics. I use washing soda, or sodium carbonate, in the dye process to set the color. I have never had my hand dyed fabrics run or bleed. You only need to use it once, no need for the over and over. If using for new cloth, I would add about a quarter cup per gallon in a full washing machine, agitate the fabric for about five minutes, do not let the water drain but sit and soak fabric for about six hours, then continue through the full cycle and you should be good to go from then on. If you are a pre-washer then treat your new fabric this way, no need for soap and your fabric will be color fast.