Star formation history tests for ESO 443-21. In a metallicity-age grid, we show for this Voronoi bin the color-coded mass fraction assigned to different ages and metallicities summed up for both values of [Mg/Fe] (= 0.0 and 0.40 dex) The top figures show the results using limited models and a regularization = 1 (left) / 10 (right). The bottom figures show the results for the full range of models and a regularization = 1 (left) / 10 (right).