Batiks can be like any other fabric. Some dark colored fabrics bleed and some do not. I would do just what you said, contact the company and see what they say. Once the fabric is treated, I would think a couple of washings would remove the chemical treatment. So far the batiks that I have bought have all been color fast, including the reds and blacks. I cut a small piece off of the corner and place it in very warm soapy water to check for bleeding. Hopefully what you buy will not need any treatment and it will not be a concern.