Abstract: A thermally sensitive record material is disclosed which comprises chromogenic material which is a mixture of the isomers 7-(1-ethyl-2-methylindol-3-yl)-7-(4-dimethylamino-2-ethoxyphenyl)-5,7-dihy drofuro[3,4-b]pyridin-5-one and 5-(1-ethyl-2-methylindol-3-yl)-5-(4-diethylamino-2-ethoxyphenyl)-5,7-dihyd rofuro[3,4-b]pyridin-7-one. This record material has superior color forming efficiency and greater image stability, especially resistance to fading in incident light.

Abstract: A thermally sensitive record medium is disclosed. Data is generated on the record medium in response to an application of heat. The record medium is capable of generating data images in more than one color by exposing the medium to more than one temperature level in areas to be imaged. Overlap or interference between two colors is avoided by utilizing at least one color-forming system which requires a thermal decomposition of one system component before it can be reacted to yield color.The record material is made by coating individual layers, each containing a color-forming system or preferably by coating a single layer including all of the color-forming systems.