You can use any kind of paint or ink. I used regular acrylic paints since I had a supply from a painting class and want to use them before they dry out. To get my colors, I mixed ceruleuan blue, ultramarine blue, a little cadmium yellow light, and a lot of titanium white. I added an equal amount of fabric painting medium so that it would play well with fabric (although I don't think that is necessary).
I spread the paint with the brayer onto the gelatin plate and then pressed a toilet paper roll here and there onto the plate to get oval shapes and then laid down a piece of cotton muslin and pressed it down evenly and lifted it up. I sprayed water onto to the plate and used a clean piece of cloth to wipe up the extra paint and got a nice pattern on that cloth, too. I repeated several prints with various patterns for about 10 cloths.
Then, to get gray, I added a little cadmium light to the blue mixture and some more fabric medium and some more white. Here are two of the prints.
After the paint dried, I used Shiva Paintstiks, which are oil paints. I found out that you can use the oil paints on top of acrylics without a problem, but you cannot use acrylics or other water-based paints on top of oils. Anyway, what I did was to put texture plates under the fabrics and then rub the sticks on top to get patterns and layers of patterns. I pressed the oil sticks first onto a plastic plate and mixed the colors with a palette knife to get colors I wanted and loaded stencil brushes with the paint and then rubbed the brushes across the fabric that was on top of the texture plates. (One of the texture plates was actually a brass trivet that I bought at a thrift shop.)