Josef Albers and Victor Vasarely are one of the founders of Op Art and is considered as one of the most important German painters. Albers experimented a lot with the concerted action of colors, shapes, lines and planes, with the subjectivity of visual perception: "Just the appearances are not deceptive." In this context his most famous series "Homage to the Square" is one whose images are always the same three or four nested squares of different colors. The colors are never mixed, but applied directly from industrially manufactured paints, the article numbers are noted on the back of the pictures by the painter.
Josef Albers was a participant in documenta 1 and documenta 4 in Kassel.