if you visit the Dharma Trading Company website they have very good instructions for dyeing fabrics- along with tips, hints, help & inspiration. make sure your fabric is 'pre-washed' with detergent- no fabric softener. I generally use a Tupperware tub, or some sort of plastic container with a lid. do not use anything (tools, containers) that will later be used for food prep- have separate measuring spoons, stir sticks, containers ect. I have always used soda ash- along with salt *the salt helps 'push' the dye out of the water & into the fabric (soda ash is a 'fixative' which makes the dyes bond with the fibers and not just sit on top of the fabric) mix up your dyes, mix up the soda ash/salt mixture (1 cup soda ash, 1/2 cup salt, 1 gallon water-- mix/stir well until completely dissolved) you don't mention how large of a piece of fabric you intend to dye- so, i'm going to 'guess' 1 yard---(in class we use gallon ziplocks for this- so i'll tell you with those- you can use what ever container you have decided on) set ziplock in a plastic dishpan so they stand up-open. (btw- the soda ash/salt mixture will last a long time so can be stored in a lidded container for future projects) have 2 containers of clean water close by- one for rinsing hands/tools, the other to use in the process--fill them with HOT water to start. measure clean warm water into bag (4 cups for 1 yard of fabric) add the amount of dye using (mixed up ready to use) scrunch up the fabric & add to the bag * I use a chopstick to push it down into the water/dye solution* make sure the fabric is completely covered. add the soda ash/salt mixture to the bag (1/4 cup for 1 yard fabric) press/massage the bag to mix the dye solution-soda ash together use your hand to separate the fabric in the bag so everything is evenly distributed. zip up the bag & set aside. for even color 'massage' the bag every 10 minutes for the next 90 minutes (if you want mottled you can let them sit without moving for at least 1 hour) *I generally leave my fabrics in the dye solution for at least 24 hours* == the next day start your washing machine-and add about 1 tbsp. Synthropol- rinse the fabrics you have dyed in the sink with cold water- then add them to the washer as it fills- I usually wash my fabrics 3 times then into the dryer. dyeing is a wonderful *technique* to learn- then you can always 'create' your fabrics in the colors you need.
I recommend 2 books if you are going to *make a habit of it*=== the Fabric Dyer's Dictionary and Fabric To Dye For= both are great resources.