A single-sheet multilayer thermal imaging system consists of three color-forming layers comprising materials that are transformed from a colorless crystalline form to a colored amorphous form by heating. The color-forming layers are separated by thermally insulating layers, allowing for independent addressing of each color-forming layer (i.e., without any undesired color formation in other layers). The temperature required for the conversion from the colorless to the colored form is different for each of the color-forming layers. It may be difficult, however, to find suitable color-forming molecules having the right properties for image formation (e.g., chromophore and stability characteristics) as well as an optimum melting temperature. Incorporation of additional components into the color-forming layers allows the placement of the same color-forming crystalline material in any layer of the imaging system, eliminating the constraint of its intrinsic melting temperature.