Magnetically responsive photonic crystal structures have been produced by self-assembling superparamagnetic colloidal particles under the balance of repulsive and attractive interactions. The optical properties can be tuned rapidly, widely, and reversibly in the entire visible spectrum. By taking advantage of many unique features of the field responsive systems, we demonstrate in this article some of their niche applications for various display purposes, including antifraud devices, rewritable photonic papers, and full colour high resolution printing systems.