Understanding light- and storage stability is of utmost importance in inkjet printing. In this paper we present investigations of light-induced kinetics of dye degradation. Magenta black and cyan dyes are irradiated on typical glossy and matt media using a Xenon lamp and the decrease of remission intensity with irradiation time is recorded using UV-Vis spectroscopy. Most dye kinetics can be described as 1^st order reaction at least in the beginning of the reaction. From temperature dependence of 1^st order kinetics we are able to determine activation energies for the decay process allowing us a detailed media-dependent comparison of kinetic behaviour. Furthermore an analysis of UV-Vis spectra show that not only one single degradation channel is responsible for light fading processes.In order to define the contribution of oxidative non-light induced processes UV-Vis data of dark storage under oxidative atmosphere are compared in shape and intensity allowing a separation of light and oxidative decay channels. For most ink-paper combinations a superposition of light-induced and oxidative mechanisms are likely. Using activation energies as parameter for dye-paper stability also the influence of room humidity on stability of inkjet prints can be estimated.