Name: Katie
Message: Ive got a blouse that is 63% rayon, 34% polyester, and 3% spandex. Should I dye it with the Rayon procedure or the polyester procedure to turn the blouse from brown to dark red?

Because all dye is transparent, you can use dye only to turn fabric from a lighter color to a darker one, never to a lighter color. Is your brown light enough to be overdyed to make a dark red? Most browns are not. You may have no choice other than black.

Your blouse contains twice as much rayon as polyester, so it makes sense to concentrate on dyeing it only.

It is much easier to dye rayon, using cool water fiber reactive dyes, than to dye polyester. Polyester requires a special sort of dye which is not at all suitable for beginners. Rayon can be dyed with the same Procion MX dye that is used for tie-dyeing cotton. In order to get a smooth solid color, I recommend that you use the washing machine for your dyeing; see, for example, PRO Chemical & Dye's recipe for "Immersion Dyeing in the Home Washing Machine using PRO MX Reactive Dyes".