...that on natural fibers, Fiber Reactive Dyes are considered more permanent than most any other type of dye?
Fiber Reactive dyes actually have a chemical reaction in the presence of a Ph altering "fixative" like Soda Ash, causing them to form a chemical bond and become a physical part of the fiber molecule. Once the excess "leftover" dye is washed out thoroughly, the rest will not come off except in the presence of bleach or other "discharge" chemicals. This is in contrast to "all purpose" or "direct" types of dye which work by "staining" the fibers with the assistance of heat in the form of hot dye baths or steaming. Vat dyes are another type, which have to be made soluble in water with "reducing agents" like lye, and insoluble on fabric with "oxidizing agents" or air exposure. Natural Indigo is one of those, and it can fade and rub off.
Clothing properly dyed with Fiber Reactive dye, and washed according to direction to remove the excess, is safe for babies because it will not come off in their mouth or on their skin. With other types of dye, a bit will wash out every time the garment is washed, which means it fades much faster, and could come off in the presence of rain, sweat or baby saliva! Fabrics properly dyed with Fiber Reactive dye won't bleed on the rest of your laundry either, as long as the rinse and washout procedure was followed. You can wash your tie dyes with your white stuff! This also makes it better for hand dyed quilt fabrics than imported dyed cloth where you have no idea what it was dyed with. We hear about those unhappy accidents all the time!
The Procion type Fiber Reactive dye carried by Dharma Trading has the added advantage of not needing a lot of heat like the other Fiber Reactive dyes (Remizol, Vinyl Sulphone, Cibacron, etc.), or like Acid Dyes (for wool & silk) or Vat dyes, Natural Dyes and all purpose or Direct dyes. This is because it is a more highly chemically reactive or sensitive molecule, and therefore the necessary reaction can take place at room temperature (above 70°F) with the proper use of the fixative and time. This makes it far superior for multiple color Tie-Dye and Batik (because it won't just melt the wax) than any of those other dyes. And since it is such a versatile dye, you can also use it for screen or block printing, painting, spraying, stenciling, etc. Unlike paint, dye leaves no feel on the fabric, so for some applications, you can used thickened dye instead of paint. Check out all of our various directions for these different uses, including normal tub dyeing, and have fun!