In one example, a lighting device for an additive manufacturing machine includes first light sources each to emit monochromatic light within a first band of wavelengths that includes a peak light absorption of a liquid coalescing agent and second light sources each to emit monochromatic light within a second band of wavelengths different from the first band of wavelengths. Each of the first light sources or each of multiple groups of the first light sources is individually addressable to emit monochromatic light independent of any other of the first light sources or of any other group of the first light sources and each of the second light sources or each of multiple groups of the second light sources is individually addressable to emit monochromatic light independent of any other of the second light sources or of any other group of the second light sources.