Wooden Paint brushes with pig hair, Acrylic paint, Variable dimensions

Rainbows found in landscape painting in the past 1600 years were discovered to vary greatly in color and and order of hues.  Some of the rainbows in fact had little to do with the scientific analysis of the rainbow and reflected instead cultural factors, like the colors of clothes worn by the king.  Acrylic paint was first used to copy a section of a found rainbow upon a piece of 3 meters Fabriano paper.  Next a large 13 or 15 inch brushes were pulled through the paint in one brushstroke to create the painting.  This process left an afterimage of paint on the brush and the brushes were hung on the wall.