Menthe Wells is listed as a synesthetic artist (also spelled synaesthetic). Synesthete artists are listed for reference with explanations. This is the only recognized site that carries the explanations and understandings and communicates the synesthete artist listing.
http://www.daysyn.com/synesthete-artists.html#anchor_106
Please check the site listing to see the explanations and other artists such as
Hockney and VanGogh.