Shelf legibility and viewing conditions
Packaging color operates under simultaneous constraints that screen design does not: it must work at 3 meters distance, from a 90-degree side angle, in variable retail lighting ranging from warm incandescent in specialty retail to cool fluorescent in supermarkets, and in direct visual competition with adjacent products. The color decision that works in isolation in a design review may fail at shelf when placed next to the competitive context it will actually appear in. Proper packaging color evaluation requires a shelf simulation: mock-up at scale, placed in a competitive context, viewed under relevant retail lighting conditions.
