Photographer. Light.

Louis Kahn once told of a task he imposed upon himself.
“I gave myself an assignment: to draw a picture that demonstrates light. Now if you give yourself such an assignment, the first thing you do is escape somewhere, because it is impossible to do. You say that the white piece of paper is the illustration; what else is there to do?  But when I put a stroke of ink on paper, I realized that the black was where the light was not, and then I could really make a drawing, because I could be discerning as to where the light was not, which was where I put the black. Then the picture became absolutely luminous.”
Even the artist must invoke darkness in order to illustrate light.

From Catching the Light: The Entwined History of Light and Mind
by Arthur Zajonc