This background is a brushed rubber cement resist, with watercolor. The prickly pear is painted with gouache. Here he is with his partner on a drizzled rubber cement resist:
Here you've caught me trying out my new gouache. Even though it is a Reeves starter set it is reasonably well pigmented. I'm looking forward to trying it out with a dip pen as well. That will have to wait until I'm home again with my calligraphy supplies.