Abstract

In this work the study of the green pigments employed by ancient Romans in the decoration of 50 wall fragments from buildings of different ages located in seven archaeological sites of the Augustean X Regio (Venetia et Histria) is presented. The pigments are green earths—celadonite and glauconite, the latter associated to variable amounts of smectites—as found through mid-Infrared Fourier Transform Spectroscopy and as confirmed by Principal Component Analysis. The investigation was performed in suitable spectral ranges that while accounting for all the most intense absorptions of green earths allowed to minimize the influence of absorptions due to accessory minerals in the pigment ores or to the mineral species contained in the preparatory layers of the painted fragments (carbonates, quartz, kaolinite and gypsum) and sampled with the pigment. Three commercial green pigments consisting of the minerals celadonite and glauconite were also considered to check the soundness of the approach followed for the identification of the historical pigments and the reliability of the results obtained. For the first time it is shown that Principal Component Analysis is an effective tool to confirm the results of conventional spectroscopic analysis of the two green earths celadonite and glauconite.

摘要

在这项工作中，研究了古罗马人在装饰来自位于奥古斯都十区 (Venetia et Histria) 七个考古遗址的不同时代建筑物的 50 块墙壁碎片时使用的绿色颜料被呈现。颜料是绿土——青钙石和海绿石，后者与不同数量的绿土有关——通过中红外傅里叶变换光谱法发现并通过主成分分析证实。调查是在合适的光谱范围内进行的，同时考虑到绿色地球的所有最强烈的吸收，允许最大限度地减少由于颜料矿石中的副矿物或彩绘碎片的预备层中包含的矿物种类引起的吸收的影响（碳酸盐、石英、高岭石和石膏）并与颜料一起取样。还考虑了由矿物绿钙石和海绿石组成的三种商业绿色颜料，以检查用于鉴定历史颜料所遵循的方法的可靠性和所获得结果的可靠性。首次表明主成分分析是一种有效的工具，可以确认两种绿土绿钙石和海绿石的常规光谱分析结果。