These were both projects from my media class using a gouache resistance technique. Basically you take some illustration board and paint the image out with white gouache. Once that dries you evenly brush india ink over it (I used black in the case, but you could use any colour). Once that dries, you run water over the whole piece in the sink and the white gouache washes away, leaving an almost woodblock-print-like image behind. It's so much fun to work with and you can get some really interesting spontaneous textures out of it.