An apparatus and method for catalyzing a reaction on a substrate (24) comprising, a light source (12), a micromirror (16) positioned to redirect light (14) from the light source (12) toward a substrate (24) wherein the redirected light (14) catalyzes a chemical reaction proximate a substrate (24), is disclosed. A computer (18) is connected to, and controls, the positioning of mirrors within the micromirror (16) to specifically redirect light to specific portions of a substrate. The substrate (24) can be placed in a reaction chamber (50), wherein the light (14) that is redirected by the micromirror (16) catalyzes a chemical reaction proximate a substrate (24).