Inkodye is a light sensitive dye which can be used on cotton, wood, suede, silk and other natural fibers. As of right now, I think it only comes in blue, orange and red, but you can mix the colors. I first read about it on the blog How About Orange. The easiest method seems to be making stencils or using pre-existing objects to block the light (photograms). You can add water to adjust the concentration of the dye. For this first experiment I used about 2 fl oz of dye, approximately a 1/4 cup of water, light-weight white cotton fabric and card stock paper for the stencil.
I laid out the fabric on a piece of board, brushed on the dye solution till the fabric was fairly saturated, placed the stencil on top, then left it out in direct sunlight for 10+ minutes. (Were I to do this again, I would cut the stencil out of a waterproof, opaque material, lay it on the fabric and then brush on the solution).
Then I rinsed the fabric and hung it up to dry.Some things I learned during this process, which may help you if you try it:
1. Being a photosensitive dye, I was worried that working under fluorescent lights would cause the solution to develop before I could use it, so I kept covering up the unused solution and only taking it out as needed. But as I kept working, I realized that the solution seemed unchanged and I was able to leave it exposed to the artificial light without any problems. The instructions on the bottle say "sunlight" but I've seen videos where it developed under artificial light, so maybe it depends on the concentration of the dye, or the type of artificial light you are using.
2. Wash your fabric thoroughly with soap after the developing process. I only rinsed mine with water and while it was hanging up to dry, the white areas kept slowly developing and turned a light blue (they were hanging in the sun to dry, like the above photo). And even after a week, I left the pieces near a window and they continued to change color. So lesson learned, wash thoroughly, or make sure the area under your stencil doesn't get any dye.
3. I wanted to see if I could get negatives to develop (see below), so I laid them on a transparent sheet of plastic (to protect the negatives from the dye) and then covered that with saran wrap. I also taped the corners down so it would lie flat. As you can see, even though it was clear plastic, it didn't fully develop. So you might need an undiluted dye concentration if you plan to do something like this.