That question is so big that there is no end [Albers refers here to the relationship between colors and the source of light]. You see, they have just you cannot participate with it if you have not lubricated your eyes very thoroughly to see the little changes produced in our eye that has another action than any optical apparatus like photography. We must know that we have two ways of seeing. For instance, when we are indoors another part of the retina is engaged compared with when we are outdoors. If we are in warm light or cool light, in higher light or lower light.

'Oral history interview with Josef Albers' (1968)