A system for configuring and utilizing J electromagnetic radiation sources (J≧2) to serially irradiate a substrate. Each source has a different function of wavelength and angular distribution of emitted radiation. The substrate includes a base layer and I stacks (I≧2; J≦I) thereon. Pj denotes a normally incident energy flux on each stack from source j. In each of I independent exposure steps, the I stacks are concurrently exposed to radiation from the J sources. Vi and Si respectively denote an actual and target energy flux transmitted into the substrate via stack i in exposure step i (i=1, . . . , I). t(i) and Pt(i) are computed such that: Vi is maximal through deployment of source t(i) as compared with deployment of any other source for i=1, . . . , I; and an error E being a function of |V1−S1|, |V2−S2|, . . . , |VI−SI| is about minimized with respect to Pi (i=1, . . . , I).