It is a work in which the irises were drawn on a golden screen. This elegant flower painting is a design that had been from the Muromachi Period as a motif to recall a scene of Ise-Monogatari, and he also used it for the lacquer work and inkstone before the folding screen.
The mineral pigments were used for coloring in blue(ultramarine) and green (verditer) which clearly appears in the golden background.
You may think that each plant are drawn in a plane. However, when looking at the whole from a little far away, you would notice that irises are lined up in three dimensions.