We are going to do some tie dying this weekend. It should be exciting. Will be using Procion MX for the dye. The procedure I use to dye cotton is to prewash and wet the goods, add dye and salt to water, stir and add the goods stirring for about 15 minutes.
Dark colors take longer.
All that's needed is a gentle rinsing after and a mild wash. Synthropol is not really necessary. Just be prepared to rinse a lot. Let me know. Before posting a message, please be sure you are in the appropriate category.