• P, p, F, f, C, c, O, o, E, e = Uppercase letters refer to Raman spectra, the corresponding lowercase letters refer to fluorescence spectra The letters means: C = Casein tempera, E = Egg tempera, F = Fresco, O = linseed oil, P= Pigment dry. The painting techiniques are distinguished by this colour scheme:
• — pigment dry 531.5
• — pigment dry 632.8
• — pigment dry 780
• — fresco
• — casein tempera
• — egg tempera
• — linseed oil
• 5, 6, 7 are used to distinguish the laser excitation, rispectively, at 531.5, 632.8, 780 nm.
• A5, A6, A7 = All spectra, acquired with one laser exitation and showed superimposed. To evidence the shifts and the variations in intensity, the spectra of dry and applied pigments have been presented superimposed. The positions of the peaks are indicated by guide lines, adopting the following procedure.
  1) If the spectrum of the dry pigment is available, the corresponding peaks are indicated. Otherwise, the positions of the peaks of those spectrum, obtained from the applied pigment, with the best signal- noise ratio are shown.
  2) If the spectra of applied pigments contain more peaks than those present in the spectrum of the dry pigment, these peaks are indicated, adding the code for the binding agent to their label.
• CP,CF, CC, CO, CE = Comparison of the Raman spectra, acquired with all the 3 laser excitation,.of the pigment dry and painted.
• 5F, 6F, 7F = Comparison of the fluorescence spectra, acquired with one laser excitation.of the pigment dry and painted.
• T5, T6 = Peaks' tables. The peaks’ tables show the positions of the peaks of the dry (P) and applied pigment (C, E, F, O) spectra, together with the shifts with respect to the dry pigment. The spectra acquired with excitation at 531.5 nm and 632.8 nm are indicated adding, respectively, ‘5’ or ‘6’. If the spectrum of the dry pigment is not available, the shifts are calculated with respect to the spectrum of the applied pigment with the best signal-noise ratio. This reference spectrum is indicated by an asterisk.

Notes: * Imperial purple was not applied because its use is not documented in any of the four painting technique. ** Orpiment was not still applied in any of the four painting technique.