Thermal dye transfer printing has become accepted as a source of high-quality color hardcopy output. In this process, heat is used to transfer dye from a dye donor ribbon to a receiver sheet. The amount of dye transferred to the receiver sheet is proportional to the amount of thermal energy supplied to the dye donor ribbon. With this technology, it is straight forward to print a 2-to-8-bit tone scale which is necessary for a photographiclike appearance. With is technology, printing of digital images from a variety of applications--which include video, medical, and high-end computer graphics--is possible. Although this technology is capable of generating color hardcopy output with a photographiclike appearance, it is often the case that such output will not have the same image stability characteristics as conventional AgX photographs. Photographic prints are exposed to light, heat, oxygen, water, and fingerprints in normal handling. In this paper, techniques are described to characterize the image stability of thermal dye transfer prints. The results of these studies show that there are both similarities and differences in the image stability of thermal dye transfer prints and conventional photographs.