The effects of exposure to ultraviolet radiation on the fluorescence and phosphorescence intensity of impurities in nylon 66, sometimes called gel, were measured using color image processing. The fluorescence intensity of the gel particles and of the polymer showed an approximately exponential decay with the time of exposure to ultraviolet radiation, with decay constants in the range 0.5 to 1.0 h(-1). Analysis of images that were acquired over several hours also indicated a decrease in the phosphorescence intensity of the gel particles. Image processing provides a simpler and less expensive method of luminescence analysis than the spectroscopic techniques used previously to examine the effects of exposure to ultraviolet radiation on the phosphorescence properties of nylon 66 impurities.