Fiber Reactive Dye
Fiber Reactive Dye is the best type for cotton and natural fibers. Compared to other types, fiber reactive dyes are brighter, easier to use, and don't fade.
Natural color pigments provide the color for all dyes; from simple all-purpose dye to more advanced fiber reactive dye.
Fiber reactive dyes work like magic. They form a covalent bond (when atoms share electrons) with cellulose fiber molecules. In other words, when the dye sets the dye molecules are literally part of the cellulose fiber molecules.
Fiber reactive dye chemistry is a huge topic. If you want to know what is fiber reactive dye or a fiber reactive dye definition go to About Fiber Reactive Dyes at Paula Burch's site. It's an older looking site, but it's an amazing resource.
Why Procion dyes
In addition to being brighter, more colorfast and longer lasting, Procion dyes are the best because they're easy to use.
Procion dyes are relatively non-toxic with a low ideal reaction temperature 30C° (86°F). This means you can dye at room temperature without adding heat to set the dye.
And they don't fade so you can wash them with your whites and not worry about color bleed.
Procion dyes were originally produced by Imperial Chemical Industries (ICI) in 1956. Dystar owns the brand name now, but the patents have expired so generics are available as dichlorotriazine or as Procion type dyes.
We buy Dharma Fiber Reactive Dye from Dharma Trading It's great and their service is excellent.