CYANOTYPE (n.) A photographic process in which light does the forgetting. What is exposed becomes dark. What is held back becomes the figure — pale, preserved, almost. See also: blueprint, absence, the shadow that outlives the object casting it. Distinguished from other processes by its refusal of grey: you are the deep Prussian field, or you are the light that burned through. There is no middle record. The branching at the top — that is not decoration. That is the image thinking.