I did a lot of thinking and some research. I found a medieval representation of a mermaid. Caoilfhionn also has blue and white flowers as her badge and I wanted to incorporate that into the design.
I used Black Arches paper, 80 pound, with miniatum ink not regular miniatum because I wanted to make fine lines. The white ink was Dr. Martin's White Ink and the paint was Holbein or Windsor Newton goauche.