Irradiation cycling was performed to evaluate the ageing of the redox process observed on cerium-doped Rb2KInF6 compounds. An on-off switch of monovalent indium luminescence is observed for the lowest cerium doped material, whereas a nice colourimetric contrast between a bluish-green and orange emission is generated for the material with the highest cerium content. Photoluminescent properties combined with X-ray diffraction, chemical analysis and magnetism measurements allowed an accurate characterization of the system. A complete explanation of the optical behaviour is therefore proposed. Finally, printing tests were performed to illustrate the good functionality of the prepared materials for UV sensitivity.