With the penetration of inkjet printers into the professional photographic market, image permanence of the prints produced on an inkjet printer has become a much-debated issue. One of the factors affecting the image permanence is the effect of ozone. Certain organic dyes present in the inkjet inks have been found to be vulnerable to degradation by atmospheric ozone, a strong oxidizing agent.In order to understand and observe the effect of simulated ozone exposure on prints made on an inkjet printer, tests were performed under controlled conditions. We believe this to be the first such test performed on inkjet prints by an unbiased third party. The results did provide indication that the degradation of the prints had some dependency on the substrate. The results showed that for one particular dye colorant set the fading of Cyan colorant caused objectionable color differences. Compared to dye based colorant, pigment colorant set proved to be very stable. Two different substrates on a pigment based inkjet printer and four different substrates on a dye based inkjet printer were tested.