an alteration product of malachite, orpiment, and vermilion, both alone and in
combination and finely a very interesting gilding technique that used pararealgar
with traces of orpiment and vermilion [76].
The group from Parma developed analysis of the palette of pigments used in the
mural painting in Pompeii and identified original pigments found in bowls discovered there [77]. The influence of the different environmental conditions on the
state of wall painting in Pompeii became the object of the comprehensive study
carried out by Madariaga and co-workers. The group from the University in Bilbao
applied the Raman spectroscopy combined with other analytical techniques to the
characterization of the original composition and decay products in the mortars and
pigment layers [78], the blackening of red cinnabar, efflorescence [79], a severe
chemical attack of the acid gases on the murals after the eruption of the Vesuvius
volcano [80], and study of salts formed in protected wall paintings and the
mechanism of the decaying process [81].
Contemporarily to research of the wall paintings, one of the first applications of
the Raman spectroscopy in the study of the prehistoric rock art was published by
Smith et al. [82]. In the microsamples collected from the red and black parts of
Paleolithic paintings collected from the three caves situated in the Lot Department
in France mineral pigments: haematite, goethite, amorphous carbon, and manganium oxide/hydroxide were identified. Then, in the same year, the chemical and
mineralogical study of ancient paints from the prehistoric rock paintings from the
Big Bend region of Texas was reported [83]. The application of Raman spectroscopy supported by the FTIR, XRD, and GC-MS analyses allowed characterization of the paint materials, including pigments and binders, and established the
relationship between the paints and the environmental matrix, which included
calcium sulfate (gypsum) and calcium oxalate monohydrate (whewellite). The
systematic study of the caves decorated by prehistoric paintings [83] and situated on
the Iberian Peninsula was started by Hermanz few years later. His investigations
encompassed the characterization of the chemical composition of pigments, identification of the components present in the crusts (whewellite, weddellite, and
amorphous carbon), and elucidation of the mechanism of sandstone weathering
process [84], revealing the nature and distribution of the components of the oxalate
layers: alpha-quartz, haematite, whewellite, gypsum, muscovite, microcline, anatase, and rutile [85], identification of the rarely used white pigment (a-quartz,
anatase, muscovite and illite), identification of whewellite and weddellite as
products fungi or lichens activity (e.g., Verrucaria nigrescens) [86], characterization of oxalate accretions of whewellite and weddellite on post-Paleolithic rock
paintings from open-air rock shelters of Triassic sandstone in the Sierra de las
Cuerdas (Cuenca, Spain) [87], and analysis of pigments from the caves from the
Tito Bustillo and El Buxu Caves, Asturias [88].
Molecular identification, by Raman spectroscopy, is particularly reliable in the
analysis of materials with crystalline structure [89], like minerals. In the CH field,
the study of minerals as raw structural materials [90] or pigments [91] played an
important role in the understanding of the nature and the internal structure of the
artifact. The synopsis covering the last decade of the applications of Raman
16 Spectroscopy in the Analysis of Artworks
489
combination and finely a very interesting gilding technique that used pararealgar
with traces of orpiment and vermilion [76].
The group from Parma developed analysis of the palette of pigments used in the
mural painting in Pompeii and identified original pigments found in bowls discovered there [77]. The influence of the different environmental conditions on the
state of wall painting in Pompeii became the object of the comprehensive study
carried out by Madariaga and co-workers. The group from the University in Bilbao
applied the Raman spectroscopy combined with other analytical techniques to the
characterization of the original composition and decay products in the mortars and
pigment layers [78], the blackening of red cinnabar, efflorescence [79], a severe
chemical attack of the acid gases on the murals after the eruption of the Vesuvius
volcano [80], and study of salts formed in protected wall paintings and the
mechanism of the decaying process [81].
Contemporarily to research of the wall paintings, one of the first applications of
the Raman spectroscopy in the study of the prehistoric rock art was published by
Smith et al. [82]. In the microsamples collected from the red and black parts of
Paleolithic paintings collected from the three caves situated in the Lot Department
in France mineral pigments: haematite, goethite, amorphous carbon, and manganium oxide/hydroxide were identified. Then, in the same year, the chemical and
mineralogical study of ancient paints from the prehistoric rock paintings from the
Big Bend region of Texas was reported [83]. The application of Raman spectroscopy supported by the FTIR, XRD, and GC-MS analyses allowed characterization of the paint materials, including pigments and binders, and established the
relationship between the paints and the environmental matrix, which included
calcium sulfate (gypsum) and calcium oxalate monohydrate (whewellite). The
systematic study of the caves decorated by prehistoric paintings [83] and situated on
the Iberian Peninsula was started by Hermanz few years later. His investigations
encompassed the characterization of the chemical composition of pigments, identification of the components present in the crusts (whewellite, weddellite, and
amorphous carbon), and elucidation of the mechanism of sandstone weathering
process [84], revealing the nature and distribution of the components of the oxalate
layers: alpha-quartz, haematite, whewellite, gypsum, muscovite, microcline, anatase, and rutile [85], identification of the rarely used white pigment (a-quartz,
anatase, muscovite and illite), identification of whewellite and weddellite as
products fungi or lichens activity (e.g., Verrucaria nigrescens) [86], characterization of oxalate accretions of whewellite and weddellite on post-Paleolithic rock
paintings from open-air rock shelters of Triassic sandstone in the Sierra de las
Cuerdas (Cuenca, Spain) [87], and analysis of pigments from the caves from the
Tito Bustillo and El Buxu Caves, Asturias [88].
Molecular identification, by Raman spectroscopy, is particularly reliable in the
analysis of materials with crystalline structure [89], like minerals. In the CH field,
the study of minerals as raw structural materials [90] or pigments [91] played an
important role in the understanding of the nature and the internal structure of the
artifact. The synopsis covering the last decade of the applications of Raman
16 Spectroscopy in the Analysis of Artworks
489