In recent years, thermal transfer systems have been developed to obtain prints from pictures generated electronically from a color video camera. According to one way of obtaining such prints, an electronic picture is subjected to color separation by color filters. The respective color-separated images are converted into electrical signals. These signals are processed on to produce cyan, magenta, and yellow signals. These signals are transmitted to a thermal printer. To obtain the print, a cyan, magenta, or yellow dye-donor element is placed face-to-face with a dye-receiving element. The two are inserted between a thermal printing head and a platen roller. A line-type thermal printing head is used to apply heat from the back of the dye-donor media. The thermal printing head's many heating elements are heated up sequentially in response to one of the cyan, magenta, or yellow signals. The process is repeated for the other two colors. A color hard copy is thus obtained that corresponds to the original picture viewed on a screen. Subsequent to printing of the dyes, a transferable overprotective layer, or laminate, might be applied to the printed image. This overprotective layer is designed to protect the printed image from contamination by foreign material, such as fingerprints, as well as improving resistance to light fade.
Jacob J. Hastreiter, William H. Simpson, "Matte Finish on Thermal Prints" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP20), 2004, pp 976 - 979, https://doi.org/10.2352/ISSN.2169-4451.2004.20.1.art00097_2