Wet over dry - The base paint (yellow) was completely dry before applying very wet green brush stokes. The colour remains where it has been applied and it will only blend if we soften the boundaries with water. This is the best technique if you wish total control.
Dry over wet - The yellow base colour was still wet when the lines, with a brush loaded with green, were painted. As you can see, the lines blend around the boundaries between both colours. You can maintain a certain degree of control.
