Electrical components may be mounted on a printed circuit or other substrate. The electrical components may be covered with a conformal coating containing a wavelength-tuned-light-absorption-enhancement additive. The additive may be a dye or other additive that creates a light absorption peak at a given wavelength. To form openings in the conformal coating in alignment with the electrical components without damaging the components, a laser ablation tool may apply laser light at the given wavelength to the conformal coating. Openings may also be formed by placing tape over the components before the con form at coating is applied. The tape may have a color with a light absorption peak at the given wavelength to facilitate the formation of openings without damaging sensitive components.