little faint band of light turquoise
It's a narrow band of turquoise around another color. Maybe not all that light. It's a quick and easy way to tell if someone mixes their purples by combining turquoise with fuchsia. Whether or not you get a halo varies according to which other colors you mix with the turquoise. It can be hard to predict when you buy premixed dye colors.
Reactive blue 140, which is the generic name for Procion Turquoise MX-G, is the slowest-to-react of all of the Procion MX dyes. This means that it does not instantly react with the first bit of fiber it contacts. It has a little bit of time to spread out on the fabric. That means that whenever turquoise MX dye is mixed with a faster-to-react color, if you paint or otherwise directly apply it to fabric, there is a tendency for a little bit of the turquoise to separate out and make a halo around the other colors.
Reactive red 11, which is Procion Red MX-8B, also known as fuchsia, is the fastest-to-react of all the Procion MX dyes. Wherever it hits the fabric first, that tends to be where it stays. This means that anything you mix it with, if given the opportunity to spread out a bit, will form a halo around it. If you mix fuchsia with reactive yellow 86 (yellow MX-8B, which is called lemon yellow in most places but sun yellow at ProChem), to make a bright red, you're apt to find yellow halos around the red.
If you don't want to have halos, you can choose different dyes, or you can discourage spreading by adding a thickener such as alginate. If you make a bright red by mixing orange MX-2R with red MX-5B, you will not see different-colored halos around the red.
-Paula
