Tintoretto in the city of La Plata? Several investigations for the reattribution of the Portrait of Melchior Michael to Tintoretto

• A Portrait of Melchior Michael painted by the colossal Tintoretto is in the city of La Plata, Argentina. • Spectroscopic techniques were used to validate its attribution from the analytical point of view. • The detail of its arrival in La Plata also reveals the origin of this work of art. The records of the Museo Provincial de Bellas Artes “Emilio Pettoruti” (Provincial Museum of Fine Arts of Buenos Aires "Emilio Pettoruti") indicate that a work belonging to Jacopo Comin, "Tintoretto," is part of its cultural heritage, of great value to the museum and the university city of La Plata. Over time, and perhaps due to the ambitious nature of this attribution, the original assertion was called into question. A comprehensive and complementary spectroscopic analysis using Raman, FTIR-ATR and SEM-EDX techniques serves as one of the information sources for the current study. Thus, cinnabar (HgS), lead white (2PbCO 3 .Pb(OH) 2 ), calcite (CaCO 3 ), gypsum (CaSO 4 ·2H 2 O), and carbon black were determined in the artwork using the vibrational techniques while the presence of several components, such as alum (KAl(SO 4 ) 2 ·12H 2 O), calcite (CaCO 3 ), green earths (K(MgFe 2+ )(Fe 3+ Al)(AlSi 3 ,Si 4 )O 10 (OH) 2 ), lead white (2PbCO 3 ·Pb(OH)2), cerussite (PbCO 3 ), goethite (FeO(OH)), lapis lazuli, mainly composed of lazurite (Na 6 Ca 2 (AlSiO 4 ) 6 (SO 4 ,S,S 2 ,S 3 ,Cl,OH) 2 ), calcite (CaCO 3 ) and pyrite (FeS 2 ) as well as gypsum (CaSO 4 ·2H 2 O), umber (α-FeOOH·MnO 2 ), zinc white (ZnO) and lead sulfide (PbS) can be inferred from the determination of the elements using SEM-EDX studies. The tracking of the artwork and its journey to the city of La Plata, and the scanned X-Ray determination revealing hidden objects under the painting surface of the artwork are also dimensions taking into account in the present study. Thus, we can affirm the validity of the work, the Portrait of Melchior Michael, reconfirming and reattributing it to the colossal Jacopo Comin, Tintoretto.