What was Wassily Kandinsky's Color Study of Squares painted on?

Question

I have tried to find what this painting was painted on but all I can find is sites that are selling reproductions of this painting. Do you have any idea what he painted this painting on?

Answer 1

 

HERE IT IS … OIL ON CANVAS

 

Wassily Kandinsky

“Colour Study of Squares and Cycles”, 

1913, oil on canvas, 

City Gallery in Lenbachhous, Munich, Germany.