A method is developed for optimization of color rendering for a light mixture. No derivatives of the rendering function are required. Constraints of correlated color temperature and approximate white can be incorporated. The method is developed based on the Complex Method with modification. It is first applicable for 3-colors light mixtures and then extended to a
hierarchical and iterative structure for higher-order light mixtures. Applicability of the method for a mixture of four colors is demonstrated by simulation. The results show that global and unique convergence to the optimal within required tolerances for CRI and spatial dispersivity is always achieved.