In 1949 Josef Albers started his first studies, initially in black and white, for the Homage to the Square series, and worked on it until he died in 1976. It is one of several systematic examinations of the effects of visual phenomena, and shows how Albers’ approach was shaped by the Bauhaus’ educational precepts, the leading avant-garde art academy in Germany between 1919-1933, where he taught over ten years. His textbook ‘Interaction of Color’, published in 1963, shows how much the color research owes to the insights of Bauhaus masters Johannes Itten and Wassily Kandinsky. Opalescence is a property of certain colored fabrics, created by micro-structures that scatter – or possibly create interferences in – light waves. This results in a quality of semi-transparency and, depending upon the wavelength of the light involved, may cause colors to appear bluish, operating in the same way as the effect that causes the sky to appear blue. Albers translates this physics phenomenon into a painterly phenomenon by using the techniques of abstraction to turn three nesting squares in medium grey, light blue and light grey into an image of the bright, delicate sky of a summer’s morning.