Found your blog through saqa auction--I do lots of shibori and dyeing. There are ways to get deeper colors, the easiest is to make your dye solution stronger, just add more dye powder than you have been using. Also, mix 1 cup water, 1 tablespoon dye powder and 1 tablespoon soda ash in a squirt bottle, and squirt this onto a piece of fabric that's been shibori wrapped on a pole. Let it sit for a couple of hours and rinse well before taking the fabric off the pole. I get pretty good results this way. Good luck with your dyeing, you can always take the fabric you aren't happy with and overdye it, that's how I've gotten some of my favorite pieces of fabric.