In the present invention, there is provided a use of 1,1,1-tris(4-hydroxyphenyl)ethane in a composition in the formation of an image on a substrate having said composition applied thereon, wherein the image is formed upon exposure of the composition to NIR or IR radiation, and wherein the image is capable of being retained on the substrate for at least 1 day under conditions of at least 50% relative humidity. The present invention is further directed towards compositions comprising 1,1,1-tris(4-hydroxyphenly)ethane, in addition to substrates, methods of forming an image and printing processes comprising said compositions.