On Vision and Colors are, however, nonessential properties that differ according to the type of light-refracting substance that is used. The top of the upper image is violet. Below the violet is blue. The bottom of the lower image is orange. Above the orange is yellow. In this way, along with the white disk and the black background, four prismatic colors appear: violet, blue, yellow, and orange. This is in disagreement with Newton's claim that there are seven prismatic colors. As the upper image overlaps black, it is seen as violet. Where it overlaps white, it is seen as blue. As the lower image
Complementary colors sets of complementary colors which "demanded" each other. According to Goethe, "yellow 'demands' violet; orange [demands] blue; purple [demands] green; and vice versa". Goethe's ideas were highly personal and often disagreed with other scientific research, but they were highly popular and influenced some important artists, including J.M.W. Turner. At about the same time that Goethe was publishing his theory, a British physicist, doctor and Egyptologist, Thomas Young (1773–1829), showed by experiments that it was not necessary to use all the colors of spectrum to create white light; it could be done by combining the light of just three colors; red,