Synesthesia
Synesthete artists
Blanc-Gatti, Charles (1890 - 1966) 

I base my assessment that Blanc-Gatti was a synesthete mainly upon the statements by Olivier Messiaen, in his interviews with Claude Samuel (1994 (1986)). 
Hockney, David

Artist David Hockney (still alive and going strong in California), is a synesthete (see Cytowic 1989). He sees synesthetic colors to musical stimuli. In general, this does not show up in his painting or photography artwork too much. However, it is a common underlying principle in his construction of stage sets for various ballets and operas, where he bases the background colors and lighting upon his own seen colors while listening to the music of the theater piece he is working on. 
Long, Rosy -- Scottish artist.
Mackay, Jane -- British artist.  
Ryan, Barbara

An artist with polymodal synaesthesia. She works mainly with her colour to smell ( bi-directional) and spatial time unit synaesthesias. She currently lives in England.
Schimmel, Sandy -- U.S. artist (Phoenix, AZ).
Vibrato Bridge
Steen, Carol -- New York City artist. 
Last updated: 08.Aug.2014