Non-destructive and non-invasive analyses shed light on the realization technique of ancient polychrome prints.

Five polychrome prints representing famous painters, such as Albrecht Dürer, were analyzed using a non-destructive and non-invasive methodology as required by the artwork typology. The diagnostic strategy includes X-ray fluorescence (XRF), reflectance micro-infrared (microFTIR) and micro-Raman (microRaman) spectroscopy. These prints were realized with a la poupée method that involves application of the polychrome inks on a single copper plate, before the printing process.

Shift-excitation Raman difference spectroscopy-difference deconvolution method for the luminescence background rejection from Raman spectra of solid samples.

The feasibility of the shift-excitation Raman difference spectroscopy-difference deconvolution (SERDS-DDM) method for fluorescence suppression from Raman spectra of solid samples is discussed. For SERDS measurements a tunable diode laser source with an emission band centered at 684 nm is coupled to a conventional micro-Raman apparatus and a monochromator device is used for checking the excitation frequency stability. The shifted Raman spectra are then mathematically treated and a deconvolution procedure is used to reconstruct the Raman spectrum devoid of fluorescence.

The Raman spectrum of hematite: possible indicator for a compositional or firing distinction among Terra Sigillata wares.

The Raman spectrum of hematite (alpha-Fe2O3) is here discussed as a distinctive feature for Terra Sigillata sample wares. The broadening of the Raman lines and the appearance and increasing of the disorder band at 660 cm(-1), while moving from the external slip to the inner body, are proposed as valuation parameters for the study of the mineralogical composition and firing process of pottery productions.