Thermal transfer printing refers to printing processes that use heat to produce an image by either physical or chemical means or by a combination of both. Dye diffusion thermal transfer (D2T2) was developed by Sony in 1982 and has been used as a "specialist" application for graphic arts and photographic application. D2T2 printers use a print head with hundreds of tiny heating elements to molecularly transfer impregnated dyes and similar materials from a donor or ribbon onto a receptor or printing substrate. In the study reported in this paper, 81 different samples were examined, including 54 printer samples (43 photographic prints on paper and 11 plastic card samples) and 27 printer ribbons. A new thin layer chromatography (TLC) method was developed and tested, using a solvent system (80 percent n-hexane, 3 percent methyl ethyl ketone, and 17 percent ethyl acetate) that is capable of producing excellent resolution. The process proved to be effective in sufficiently resolving the dye components from a substrate that contained sublimated dyes. In many instances, physical and chemical analyses proved to be suitable tests to differentiate printers. 3 figures and 10 references