Hey, if you're dyeing cotton fabric, I highly recommend Procion dyes instead of RIT. I'm having medium to great success dyeing brown Jedi stuff with it. There is a dye fixative for Procion that works well, along with a final wash in Synthrapol (industrial-level detergent).
You can get this stuff at reasonable prices at
www.dharmatrading.com.
Deunan Shiruba