Iridescent, light-refractive visuals.

Quick answer: Holographic art uses light-diffraction effects — iridescent color shifts, prismatic shimmer, a sense of depth that changes with viewing angle — to give an image a futuristic, semi-transparent, light-based look, distinct from a flat printed color gradient. In Promptus, the Holography style preset applies that same shifting, light-refractive aesthetic automatically.