An integrated spectroscopic approach to investigate pigments and engobes on pre‐Roman pottery

Abstract

Painted Canosa ceramicswere examined to identify the nature of the pigments employed and theirmanufacturing technology.\ud A multi-technique approach was used, comprising Raman microspectroscopy and laser ablation hyphenated to inductively\ud coupled plasma-mass spectrometry (LA-ICP-MS). The analysed samples were mainly produced for burial in tombs and were not\ud intended for everyday use. They belong to the period between the end of themid-7th century andthe first half of the 4th century\ud BC, and were excavated from the Toppicelli archaeological district near the suburbs of Canosa (Puglia, Italy). Forty-eight pottery\ud fragments were available for this study. No handling of the samples was required for the Raman study, and it was possible to\ud excise the pigmented layer in such a way that the lacunae were not distinguishable to the naked eye due to the micrometric\ud size of the laser spot as far as LA-ICP-MS is concerned. Their combination turned out to be quite useful for the investigation\ud of these archaeological materials: the chemical nature of the white, red, brown and black pigments employed in the pottery\ud manufacture was investigated. Iron and manganese compounds were identified as the red and brown/black main colouring\ud substances, respectively; on the other hand, whites and engobes (whitish slips) were based on kaolinite. This set of colouring\ud substances is of importance, as it enabled the artisan to obtain in one oxidising firing cycle brown, black and red paints. Finally,\ud the finding of manganese black in these Canosa potsherds confirms that Canosa was an important centre connecting the near\ud East to central Italy and Europe since the pre-Roman age

Raman microspectroscopic analysis of decorative pigments from the Roman villa of El Ruedo (Almedinilla, Spain)

“…1590 and 1330 cm À1 , respectively, which indicates the presence of carbon. These wavenumbers depart slightly from previously reported values for Roman carbon pigments [17,20,25,26]; the differences, however, can be ascribed to differences in the conditions where the carbon material was obtained (particularly pressure and temperature, which have a decisive influence on crystallinity). Alternatively, the wavenumber differences may have arisen from experimental differences in recording the spectra; thus, the laser focal point can reach completely different temperatures during measurements, but the exact influence of variations has not yet been established.…”

“…Roman pigments have been found on highly diverse supports including wall paintings, plaster casts, mosaics and mortars, and characterised with various analytical techniques [8][9][10][11][12][13][14] including Raman spectroscopy [15][16][17][18][19][20]. Determining the particular decorative pigments used by a population can be useful to identify the specific materials available at a local, regional or even more extensive level; also, it can help better understand the basic colour preparation and application techniques used in its day.…”

A combined analytical approach applied to Medieval wall paintings from Puglia (Italy): The study of painting techniques and its conservation state

“…Colorimetric analyses showed the presence of two different yellow coloring mixtures and Raman spectroscopy permitted to identify two different pigments, goethite (α-FeOOH) and massicot; the first is a natural pigment which yields characteristic peaks at 299, 385 and 550 cm À1 , main chromophore of yellow natural pigments, [20] the second is a lead oxide which yields characteristic peaks at 145 and 280 cm À1 . [19,25] The absence of the slightly red-shift of Raman peaks to 138 and 274 cm À1 , reported in the case of massicot derived from laser thermal degradation, [26] confirms that this unusual lead yellow was employed voluntarily by the artists.…”

Micro‐Raman spectroscopy on Iberian archaeological materials

“…Finally, some types may be converted into others as a result of geologically, anthropogenically or climatically induced reactions. [19][20][21][22] In the ceramics under analysis, spinel jacobsite (MnFe 2 O 4 ) (612 and 649 cm À1 ) has been identified along with hematite (224, 290, 408 and 497 cm À1 ) (Fig. 6a), as well as other mineral phases like bixbyite (α-Mn 2 O 3 ) and hausmannite (Mn 3 O 4 ) (202, 330, 483, 618 and 695 cm À1 ) (Fig.…”