Loss of color
  • I recently completed a tie dye project with my son's class. I soaked the shirts in a soda ash bath before applying the dye (Procion MX). I then allowed the shirts to sit in zip loc bags on my very hot porch for two days. When I took the rubberbands off, all the shirts were saturated with alot of color. But after the first washing, most of the colors were washed out. I haven't had this happen before--any suggestions on why so much of the color washed out?
  • Were the shirts 100% cotton? Back before I knew better, I dyed a bunch of cotton/poly shirts and was disappointed in the results. No wonder: polyester fibers are too smooth to take the dye!
  • The shirts were 100% cotton. The parents were instructed to wash the shirts in hot water before sending them to school to remove any sizing. A friend of mine suggested my dye may have been old. I wonder what the shelf life is for powdered dye. It was mainly the "lemon yellow" that washed out; the jar of powdered dye I had was probably about4 years old.
  • The age of the dye is probably it then. Sometimes, rarely, shirts marked as 100% cotton are actually part polyester. More commonly, someone will buy "stain-resistant" undershirts, which unfortunately also resist dye. In this case, it's probably the dye, though. How frustrating it must have been to see the dye wash out.

    The typical shelf life for Procion MX type dye is one to two years after purchase. Sometimes reactive dyes will last for years longer, but often they won't. Always run a test before using any dye that is more than a year old on a large or important project.

    The fastest test to do involves the use of a microwave oven, so that you don't have to wait hours of overnight for the dye reaction. Take a small piece of fabric that you know dyes well, soak it in soda ash (one teaspoon per cup of water), then sprinkle some dye over. (Even dry dye powder will work in this test if the fabric is wet, but be very careful not to get dye powder into the air, and wear a dust mask as always when handling dye powders.) Let the dye sit on the fabric to soak in for a few minutes, then put it in a ziplock freezer bag, press out most of the air, and microwave for a few seconds, watching closely, until the steam partially inflates the bag. Stop the microwave and allow the bag to deflate. Feel the outside of the bag; if it's hot, you're done, or you can repeat the microwaving once or twice. Now you can rinse out the dye, first in cool water, and then soak it in hot water to see how much of the dye has reacted with the fabric.