I did this project for school. It's album art for Doug Burr's album, On Promenade, which is actually the best album ever.
PROCESS: I did a small thumbnail with pen in my sketchbook, then scanned it and blew it up to its final size. I then touched up the lines in Photoshop until they were crisp and clean. After that, I printed it with toner, then used a Blender marker to transfer the toner to watercolor paper, which is what gives the lines the texture. I proceeded to paint it with watercolors and then scanned it and set the type in Illustrator.