Raman Study on Pompeii Potteries: The Role of Calcium Hydroxide on the Surface Treatment

Abstract

Pottery samples from the Pompeii archaeological site were investigated by IR Raman spectroscopy and EDAX measurements. The analysis of the Raman spectra of the surfaces reveals the presence calcium hydroxide (peak at about 780 cm−1) while the calcium carbonate is totally absent. The comparative studies on the carbonation effect of the surfaces were performed on laboratory grown samples of calcium hydroxide. The samples were treated at high temperature and exposed to different ambient conditions, and the analysis suggests that the original surfaces of Roman pottery were scattered by calcium hydroxide (limewash) before the cooking process in the furnace. The result of this surface treatment not only permits a vitrification of the surfaces but also seems to reduce the content of CO2in the furnace atmosphere and then obtain a more oxidant ambient during the cooking of the pottery. These results give new insights on the real degree of knowledge of the Romans about the art of ceramics and more generally about chemistry and technologies.

Ageing of ancient paper: A kinetic model of cellulose degradation from Raman spectra

“…Recently, the exploitation of portable Near Infrared (NIR) μ‐Raman technique gave solid evidence of its usefulness in cultural heritage. Indeed, this technique grants the following benefits to the investigation of relics (such as ancient books, potteries, and cuneiform tablets): portability to afford in situ measurements without changing the conservation atmosphere of the document; tunability in the NIR range to select the more suitable excitation wavelength to optimize the signal without destroying the sample; and sensitivity, by preventing possible luminescence in the visible region because of NIR excitation . In addition, by exploiting the large penetration depth of NIR light, one can vary the focal plane of the investigated region (changing the volume of investigated sample and scanning it through the z ‐axis), thus improving information collection, eventually coupling an imaging system to improve the punctual analysis.…”

Raman identification of cuneiform tablet pigments: emphasis and colour technology in ancient Mesopotamian mid-third millennium

“…The two bands are assigned to the Calcium oxide/hydroxide (probably with different grade of carbonation as indicated in the reference [8]). The presence of Calcium hydroxide confirms the marl composition of the Kish ceramic as found in references [7, 13, 18].…”

“…In the present work, we analyzed by Micro Raman Spectroscopy some literary and administrative cuneiform tablets dated back to the mid-third millennium B.C to ascertain the presence of pigments. Raman spectroscopy, being a sensitive, non-destructive and, in the present case, portable technique, was successfully applied to investigate potteries and ancient painted walls to analyze the composition of the color [6, 7, 8]. Recent paper dealing with cultural heritage samples performed with visible excitation light, pointed out how it is possible to reach high resolution on inorganic samples [9, 10].…”

An unusual central cavity in Odontoscion dentex (Cuvier, 1830) sagittal otoliths

“…The most likely causes are physiological processes (accidental and/or pathological) that occasionally occur during the fish life cycle and which affect the normal growth of otoliths (Béarez, Carlier, Lorand, & Parodi, ). The Raman spectrum is commonly used to identify and differentiate aragonite and vaterite crystals (Chiriu et al., ; Jolivet, Bardeau, Fablet, Paulet, & Pontual, ). The herein results show that the CaCO 3 matrix of O. dentex sagittae is mainly formed by aragonite (Behrens et al., ; Tzeng et al., ).…”