Compositions and methods for production of color images which are developable with improved marking sensitivity and image contrast are disclosed and described. Specifically, a color forming composition can comprise a polymeric activator phase including a polymer matrix and an activator dissolved therein, a color former phase including a color former, and a radiation absorber in thermal contact with the color former phase. Particularly, the color former phase can be finely dispersed within the polymeric activator phase at an average particle size of less than 2 .mu.m.