El Greco (1540-1614) was a famous Renaissance artist originally from Crete whose personalized and original artistic expression gained him fame all over Europe, especially in Spain. He had many followers and his works were copied extensively. The Fine Arts Museum of Seville keeps two interesting canvases in its collection. The first one is the original El Greco work The portrait of his son Jorge Manuel (towards 1600), while the second one, The portrait of Fray Hortensio Félix de Paraviccino, was painted by an anonymous follower (2/2 16th century). The comparison of both portraits was of interest, especially with regards to the applied pigments, with the aim of finding possible similarities and differences. The elemental analysis was performed using non-destructive XRF, which permitted to examine the artworks in situ. The results of both paintings showed the use of lead white, yellow ochre, umbra, a copper-based green pigment and probably an organic red and black. But they also revealed important differences in the selection of red and blue pigments, which clearly distinguishes the original work from the anonymous one.