A substrate (114) has a first dye layer (118) that locationally changes in color to a first color upon exposure to an optical beam at a first power level, and a second dye layer (120) that locationally changes in color to a second color upon exposure to the optical beam at the second power level. The optical beam impinges a region of the substrate to render the region with a color selected from at least one of the first color and the second color. The optical beam impinges the region at a power level selected from at least the first power level and the second power level (608).