Editorial
Published online in Wiley Online Library: 8 November 2012
(wileyonlinelibrary.com) DOI 10.1002/jrs.4219
Applications of Raman spectroscopy
in art and archaeology
The Sixth edition of the International Congress on the Application
of Raman Spectroscopy in Art and Archeology (RAA 2011) was
held in Parma (Italy) from 5 to 8 September 2011, following the
tradition of biennial conferences started in London (2001).[1]
The following editions were held in Ghent (2003),[2] Paris
(2005),[3] Modena (2007)[4] and Bilbao (2009).[5]
As in the previous editions, the scientific program was focused
on the analysis by means of Raman spectroscopy of materials
related to cultural heritage and archaeology (pigments, dyes, inks,
paper, polymers, glass, ceramics, resins, fibers, corrosion products)
including topics related to natural heritage (gemstones, minerals,
fossils) and some aspects involving forensic science. In this edition,
particular attention was put on the new techniques (CARS, SERS,
resonance) and on the recent developments in Raman data interpretation (chemometrics, simulation of Raman spectra, imaging
and mapping).
These studies were presented along five Plenary Lectures,
45 Oral Presentations and 83 Poster Presentations. The number
of active participants was 130 delegates from 26 countries
among the 502 authors that presented at least one work to the
Congress. Some of those contributions are collected in this special issue, starting with a critical review by Colomban[6] on the
story of the evolution from laboratory Raman instrument to transportable, mobile and ultramobile ones, enhancing the drawbacks
and success of on-site/remote Raman analysis in cultural heritage
studies and associated fields.
Due to the increasing need for well-defined and quickly available
reference spectra, the congress was completed by a round table
about the most important criteria and requirements for the building
of a public database of standard Raman spectra of compounds
related to cultural heritage and archaeology. The results of
the open discussion have been then presented during the
Infrared and Raman Users Group (IRUG) workshop in Philadelphia
(USA, September 27–28, 2012) in order to give a contribution to
the building of the large, public, database of Raman spectra related
to art, archaeology and conservation science by IRUG. The database
will include also the big collection of reference spectra of synthetic
organic pigments presented by Fremout and Saverwyns[7] that was
presented in this RAA 2011 Congress.
Advanced methods and techniques for
complex mixtures
J. Raman Spectrosc. 2012, 43, 1523–1528
The impacts from the environment
The environmental impacts on both movable and immovable items
of Cultural Heritage were first considered in the past RAA 2009
Congress as a novel topic of interest. In this RAA 2011 edition,
this topic has attracted the attention of a considerable number
of contributors. Particulate matter, atmospheric acid gases and oxidants as well as organic compounds are the major environmental
Copyright © 2012 John Wiley & Sons, Ltd.
1523
The development of new methods and data treatment of the
spectral information will be a field of continuous research in the
field of Cultural Heritage where real samples are always complex
mixtures of original and degradations compounds that require
new approach to be implemented in the daily practice of Raman
spectroscopy. Some examples of these new developments have
been selected for this special issue, including a new concept of
detection limits for compound identification, a SERS method
for dyestuffs analysis, the potential use of Fourier transform
(FT)-Raman for quantitative analysis and the theoretical simulation
of vibrational spectra to help in the assignment of Raman signals
for unknown compounds.
The definition of Raman spectroscopic detection limits is not
straightforward, especially in art analysis where the investigation
of solid particles, often dispersed in a solid matrix of complex
nature, is involved. Vandenabeele and Moens[8] discuss some ideas
on the description of relative Raman band intensities and on how
to include this in the definition of the limit of identification with
the aim to initiate future discussions in the Raman spectrometry
community about this concept and the associated concept of limit
of identification of a product.
Casanova-Gonzalez et al.[9] have reported the SERS spectra of
carminic acid, cochineal (Dactylopius coccus), achiote (Bixa orellana),
muitle (Justicia spicigera), zacatlaxcalli (Cuscuta sp.), brazilwood
(Caesalpinia echinata) and cempazuchitl (Tagetes erecta), recorded
in aqueous solution and directly on dyed wool fibers, using silver
colloids as SERS substrate. The acquired spectra will be used to
analyse in a non-destructive way the wide variety of Mexican dyes
used since early pre-Hispanic periods for coloring fibers, codex
writing and mural painting cultural artifacts.
To determine the nature and the concentration of efflorescence
salts, ionic chromatography (IC) is generally used although the
method presents a number of drawbacks (long sample preparation
times, different sample dilutions). As an alternative, Broggi et al.[10]
proposed the application of FT-Raman spectroscopy to study the
soluble ions constituting the most diffuse efflorescence salts in
monuments and archeological sites. Calibration was set up by
measuring the band integration area of each standard salt solution
at the more intense and/or well-resolved band. Twelve control
mixtures were tested, and the obtained results were comparable
with the IC determinations performed on the same salt mixtures.
The work by Prencipe[11] shows the usefulness of theoretical ab
initio calculations to establish the Raman shifts of crystalline
materials. Such results are useful (1) for the correct assignment of
the observed Raman signals to fundamental vibrational modes,
(2) for the identification of modes too weak to be detected experimentally and (3) for the de-convolution of bands resulting from the
overlap of several modes in the experimental spectra. The procedure is exemplified using jadeite (NaAlSi2O6).
Editorial
1524
stressors affecting to Cultural Heritage materials; they affect
mainly to the outside parts of the Built Heritage and art objects
exposed to the open air. The nature of the particulate matter
can contribute not only to an aesthetical problem but to be
the nucleus for further decaying processes in the surfaces of
some materials. The aerosols containing CO2 play an important
role in the oxidation of metals (the initial acidity required to
start most of the reactions of decaying is supplemented by this
greenhouse acid gas). Moreover, infiltration waters carrying soluble
ions are another source of important problems in building materials.
Most of these effects are contained in the next nine contributions
summarized below.
As part of an air quality investigation, Potgieter-Vermaak et al.[12]
collected size-segregated atmospheric particulate matter, in a
room of the Alhambra Palace (Granada, Spain) at 100 km from
the sea, during two sampling campaigns (summer and winter).
Single-particle analyses were performed using micro-Raman spectroscopy (MRS) and electron probe X-ray microanalysis (EPXMA)
to determine its potential degradation profile. The presence of
various mixed salts of acidic and/or hygroscopic nature, such as
sodium and ammonium nitrates and sulfates, especially in the finer
fraction (to be as high as 50%), was noticeable. Apart from the
potential chemical attack, the soiling due to carbonaceous matter
deposition is a real concern; soot was identified by MRS and EPXMA
in all size fractions, reaching values of up to 55%, and was often
intertwined with soluble inorganic salts.
The evolution of green chloride and green nitrate patinas,
produced artificially on brown patinated bronze, has been studied
by Ropret and Kosec[13] using scanning electron microscopy (SEM),
Raman spectroscopy and X-ray diffraction. Cuprite and cuprous
sulfite were found on the brown patina, atacamite on the green
chloride patina, and a mixture of gerhardite and rouaite on the blue
to green nitrate type patina. Then, the green patinas were treated
in a climatic chamber for 12 weeks in a controlled SO2 atmosphere,
observing clinoatacamite and paratacamite as the end corrosion
products, after an intermediate brochantite stage on the
green chloride and green nitrate type patinas. These accelerated
experiments demonstrate the complex corrosion process of
copper-based materials.
In a second work of the same research group, Kosec et al.[14]
studied different types of bronze, brown patina and two green
type patinas (green chloride and green nitrate patina) exposed
to simulated urban acid rain, with the aim to monitor the
transformation process of chemically formed patinas and of the
bronze itself. The patinated samples were immersed in urban
acid rain, which contained carbonates, nitrates and sulfates, for
35 days to study the morphological change of the patinated
products. The structures of the patina and corrosion products
were characterized by scanning electron microscopy and energy
dispersive X-ray Spectrometry (SEM/EDX) and Raman spectroscopy.
On the brown patina, brochantite and langite formed, together
with cuprous oxide. Three corrosion products were confirmed
on the green chloride patina, that is, cuprous oxide, brochantite/
langite and atacamite. On the green nitrate patina cuprite,
langite/brochantite and gerhardite/rouaite were identified.
To complement both works, Ospitali et al.[15] characterized
Sn-based corrosion products using the hyphenated system
SEM–energy dispersive spectrometry (EDS)–Raman structural
and chemical analyser. Different Sn-containing compounds,
mainly crystalline and nanosized tin dioxides, were detected
in bronze patinas exposed to different environments like to
the atmosphere (natural and accelerated ageing conditions)
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and to the soil. These results showed that Sn(IV) oxide species
in patinas have to be systematically taken into account in order
to understand bronze corrosion mechanisms, even if they are
poorly crystallized and difficult to identify. Moreover, this
demonstrates that bronze corrosion can be fundamentally
described as a decuprification phenomenon.
To ascertain the controversial origin of the calcium oxalate
films, the settlement of their mineralogical composition and
stratigraphy was investigated by Conti et al.[16] using micro-Raman
mapping on cross section of samples taken from different facades
of the Trento Cathedral, assisted with other techniques like optical
microscopy and SEM/EDX. It was possible to directly define
thickness, composition and stratigraphy of calcium oxalate films,
identifying the newly formed crystalline phases and their distribution inside the stone. This allowed to correlate the films with the
decay of the stone. In spite of the literature data, calcium oxalate
phases are not always arranged in a recurrent stratigraphy, their
distribution is very inhomogeneous within a few microns and any
specific rule was observed for the presence of weddellite and
whewellite in the oxalate films. Moreover, the presence of weddellite
in the most external portion of the films was sometimes detected,
and the reason for such occurrence in some external parts of the
films still remains unknown.
Innovative treatments which aim at modifying existing corrosion
products into more stable and less soluble compounds while
maintaining the surface’s appearance are needed. Biological
treatments based on such criteria are being developed for the
preservation of metal artefacts. The work by Joseph et al.[17]
presents the capacity of Beauveria bassiana to precipitate copper
oxalates to stabilize soluble patinas (copper hydroxysulfates) or
the transform active corrosion products (copper hydroxychlorides)
in copper-based artifacts. Copper oxalates produce green compact
patinas showing a high degree of insolubility and chemical
stability even in very acidic atmospheres (pH < 3). In their work, cultures of B. bassiana were applied on copper-based coupons naturally aged in urban or marine environment. The results of Raman
mapping, on cross-sectioned samples, clearly showed that the original patina was gradually transformed into copper oxalates and that
the conversion is completed on the surface areas where B. bassiana
grew. Raman mapping demonstrated here to be a valuable tool for
precisely and non-destructively localizing corrosion products as
well as for evaluating protective treatments on metal artefacts.
The last work on copper patinas was presented by Bongiorno
et al.,[18] but in this case, the so-called ‘artistic patina’, an intentionally produced patina by the artist on copper based alloys,
was investigated by MRS and SEM/EDX. Several types of patinas
were experimentally produced in the laboratory using the torch
technique and reactive solutions based on water as a solvent
containing, respectively, copper nitrate, iron nitrate and potassium
sulfide (‘liver of sulfur’). Blue-green patinas showed the presence of
copper oxides (Cuprite and Tenorite), probably due to the oxidizing
treatment made with torch, and the presence of a copper nitrate
(Rouaite) due to the compositional characteristics of the reactive
solutions. Reddish-brown patina showed the presence of iron
oxides and hydroxides (Magnetite, Limonite, Goethite) together
with copper oxides (Cuprite). All the produced patinas were
then aged in a salt spray chamber and studied with microscopic
techniques, showing the formation of new highly soluble
compounds (copper chlorides, such as Botallackite, Atacamite and
Paratacamite, and copper sulfate, such as Posnjakite) that they do
not protect the metallic substrate but delay its corrosion acting as
a ‘sacrificial layer’.
Copyright © 2012 John Wiley & Sons, Ltd.
J. Raman Spectrosc. 2012, 43, 1523–1528
Editorial
Admixtures have been used since the Roman civilization with
the purpose of increasing mortar properties (hardening, strength,
etc.). In ancient civilizations, natural admixtures such as eggs,
urine, blood, etc., were used, while in current civilizations,
synthetic complex compounds are employed. Properties of
concretes are governed by its flow ability, which is related to the
dispersion of the cement particles. Better fluidity is achieved by the
addition of a type of cement admixtures named superplasticizers.
The first structural Raman characterization of a superplasticizer,
in the complex matrix of a commercial product, is presented by
Cañamares et al.[19] A third generation (polycarboxylate-based)
superplasticizer was studied at various experimental conditions, and
two different structures were determined by comparison of the
experimental Raman spectra (FT-Raman at excitation of 1064 nm)
with the theoretical ones using the DFT calculations.
To characterize possible pathologies on cementitious materials
from a historical 19th century lighthouse exposed to the open air,
in Igueldo (San Sebastian, Spain), Morillas et al.[20] used Raman
spectroscopy assisted with other analytical techniques. The spectroscopic observations were compared with quantitative concentration values of dissolved cations and anions, extracted with mili-Q
water as soluble salts and treated by chemometric tools. The
integrated analytical techniques were used to diagnose the
influence of (1) marine aerosol as source of Cl-, F-, Mg2+, Na+ and
K+, (2) seagull droppings as source of NH4+ and NO-3 and (3) original
addition of sulphates to the cementitious materials, on the
formation of decaying products such as chlorides, sulphates,
nitrates, etc. The in-situ formed decaying compounds penetrate
the pores when enough water is outside, promoting the formation
of efflorescence crusts that are washed by the rain, in a cyclic
pathway that affect the integrity of the lighthouse outdoor area
(roof and walls), leading to the formation of cracks where the water
containing soluble ions goes to the inner parts of the building.
Archaeological materials and findings
J. Raman Spectrosc. 2012, 43, 1523–1528
Paintings: pigments, dyes and binders
The study of the antique paintings is one of the most evident examples of the interaction between scientific analysts, art historians and
archaeologists, required not only to understand the problem but
also to make optimum use of the harvested data. Zoppi et al.[25]
studied several fragments of wall paintings of Phaistos (Crete); the
results gave new indications about the painting technique and
could be related to the cultural exchanges in the Mediterranean
area, between the Cretan and Aegean Bronze Age.
Copyright © 2012 John Wiley & Sons, Ltd.
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1525
The application of Raman spectroscopy to the analytical characterization of archaeological materials is now well established
although the common occurrence of fluorescence emission
backgrounds, which arise from specimen degradation, absorption
of impurities from the depositional environment or percolation of
materials from the upper parts to the archaeological site is a
problem for the analysis of some sample. That is why new improvements and experiences are required to solve such problems and to
continue the research in this particular field. Four contributions are
presented now, each covering a different type of material.
The first in-situ micro-Raman spectroscopic study of prehistoric
drawings found in the cave of Rouffignac-Saint-Cernin (Dordogne,
France) was carried out by Lahlil et al.[21] Rouffignac cave art,
assigned to the upper Magdalenian Paleolithic period (13 500–
12 000 BP), is constituted of more than 250 drawings and engraving
including 158 mammoths. There are about a hundred drawings, all
made of black pigments. Until now, destructive chemical analyses
performed on one sample, as well as recent micro X-ray fluorescence in-situ analyses have shown that the drawings contain
manganese oxides. This new study of the Rouffignac cave using a
portable Raman instrument (in-situ XRF and X-ray diffraction were
also performed to compare results) confirmed that the black
manganese oxides romanechite and pyrolusite were used as
pigments by prehistorical artists. Carbon and carotenoids have
been found locally. Differences between the various figures are
highlighted, and hypotheses about the drawings production are
proposed.
Significant paintings from the Tito Bustillo (Ribadesella, Asturias)
and El Buxu (Cardes, Asturias) caves, renowned archaeological sites
of the Cantabrian Palaeolithic cave art, were studied by MRS.
Auxiliary techniques like infrared spectroscopy, X-ray diffraction,
X-ray photoelectron spectroscopy and SEM–EDX were also used
by Hernanz et al.[22] Hematite (a-Fe2O3) of three granular sizes
(<1, <10 and <30mm) is the main red component of these
paintings. Wüstite, amorphous carbon and Mn are additional
components of some pigments. Hydroxyapatite was also detected
in one pictograph. Calcite, a-quartz and clay minerals were used as
filler materials. Particles of anatase are present in some cases, but
any organic binder was detected. Considering the main components, granular size, contents of hematite disordered structures
and secondary phases with Ni and Mn, it is concluded that none
of the pigments extracted from the Tito Bustillo and El Buxu caves
were prepared from the ochre quarry of the Tito Bustillo cave.
A representative set of eight lithic tools, suitably selected
among the very rich Palaeolithic industry collected over the past
years in different archaeological sites of the Guadalteba County
(Málaga, Spain), has been non-destructively investigated by means
of Raman spectroscopy, using both portable and benchtop Raman
spectrometers, by Hernandez et al.[23] a-quartz was confirmed as
the raw material in all the cases, although a small amount of
moganite was also evidenced as a distinctive fingerprint in these
chert samples. Crusts were mainly made of calcite in all the cases,
sometimes accompanied by other minerals such as barite or
anatase. This first Raman spectroscopic study on chert and
sandstone artefacts from the Guadalteba suggests a further and
more thorough archaeometric investigation of these lithic tools
based on sets of Raman measurements (Raman mapping) on each
specimen rather than on single-point Raman experiments such as
in the present case, given the wide macroscopic heterogeneity of
this kind of samples (color, grain size, transparency, etc.).
Finally the work of Edwards et al.[24] on the Raman spectroscopic
analysis of biomaterial found in the cranial cavity of a decapitated
skull dating from the Iron Age, some 2500 years ago, must be
highlighted. The survival of brain tissue showed the presence of
degraded protein, consistent with it. The novel observation of
characteristic Raman spectroscopic signatures of biochemicals
produced by cyanobacteria, namely carotenoids and scytonemin,
both in the brain tissue and in the surrounding deposits
from the cranium, is consistent with the waterlogged depositional environment in which the human skeletal remains
were found. The Raman spectral data were in support of
biochemical, morphological and radiographic analyses of
this biomaterial, which therefore can be described as brain
that has been significantly reduced in volume inside the
cranial cavity.
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Even the most antique and well-known pigments, such as
hematite and carbon, still require deep studies to understand
their sources, preparation methods and their uses in historical and
pre-historical times. Tomasini et al.[26] suggest a characterization
by means of Raman spectra of different pigments based on carbon
to distinguish between the various kind of carbonaceous materials
used in pictorial and archaeological samples.
The analysis of the materials used in ancient artworks must not
be limited to the substances intentionally used by the artists,
because preservation along the time depends also on the
surrounding materials, on the environmental agents and on the
man-made alterations they suffer. Thus, the alteration products
and the deterioration agents should be identified and studied to
fulfill with the complete characterization of all materials present.
This cannot be afforded with the use of a single technique and
usually a multi-technique approach is required. Irazola et al.[27]
showed how the combination of portable instrumentation (Raman,
energy-dispersive X-ray fluorescence – EDXRF-, infrared diffuse
reflectance – DRIFT-spectrometry) and laboratory instruments, like
Raman imaging and SEM–EDS can be fruitfully used to assess the
conservation state of 16th century wall paintings located in
two churches of the Biscay County (north of Spain), where
decaying products such as nitrates and oxalates, derived from
physicochemical processes on the raw materials, were detected.
The coupling between micro-Raman and chromatographic
techniques is another powerful multi-analytical approach to obtain
a contemporary identification of organic and inorganic pigments as
well as of binders, leading even to the identification of the artist
technique. Minceva-Sukarova et al.[28] used MRS, pyrolysis gas
chromatography–mass spectrometry (Py/GC/MS) and GC/MS for
the characterization of pigments and binders used in the wall
paintings ascribed to the works of the prominent 19th century
Macedonian iconographer, Dicho Zograph. The use of a huge
palette of pigments was confirmed, including both traditional
pigments, used from antiquity, and synthetic pigments, dating
back from XIX–XX centuries.
Raman spectroscopy was often used to identify traces of recent
restorations, when any documentation on the history of the artifact
can be obtained. This is the case reported by Cazzanelli et al.,[29]
where many recent restoration compounds were found in the
painting ‘Rebecca at the well’, of a Neapolitan anonymous
preserved in the MAON museum of Rende (Cosenza, Italy), were
identified. Pessanha et al.[30] reported on the study of a pair of
Japanese folding screens belonging to the early 17th century
present in the Museu Nacional Soares dos Reis (Oporto); the use
of different wavelengths as Raman excitation, together with
elemental analysis (XRF), allowed a complete characterization of
the materials present on the surface of the folding screens,
giving precious information on a restoration work conducted ‘in
the western countries’, not recorded in historical sources.
As in many other fields of the knowledge, most of the recent
developments of the Raman analysis are related to the use of the
increasing power of the computers in the interpretation of the data.
The study of modern dyes is often complex due to the presence of
a large number of Raman bands, typical of the used organic
molecules. When mixtures are present, the identification of the
minor phases is very difficult, because the bands of the different
dyes lie often in the same regions. González-Vidal et al.[31] proposed
a methodology for the automatic identification of the components
of pigments mixtures starting from the Raman spectra.
Raman spectroscopy has the invaluable ability to investigate, in
completely non-contact and non- destructive way, precious art
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objects. If the artifacts are small enough to be placed under the
microscope objective, high-resolution laboratory micro-Raman
apparatus could be used to obtained well-defined data in a safe
way. Burgio et al.[32] made an extensive comparison between
portrait miniatures realized between 16th and 17th centuries by
well-known miniaturists and preserved in the Victoria and Albert
Museum in London. This wide and detailed campaign of measurements allowed to define the evolution of the artists palettes, giving
a possible paternity for some miniatures of uncertain attribution.
Another example of use of micro-Raman laboratory equipment
without sampling is shown by Aceto et al.,[33] reporting the
results of a campaign of measurement carried on a series of early
printed decorated books. Due to the large number of studied
decorations, it was not possible to analyse all the different shades
and colors of all the pages. The combined use of fiber optic
reflectance spectroscopy with micro-Raman and XRF was very
effective to quickly identify in situ the colors, leading to the
complete characterization of the palette used in all the
analysed books.
In the study of books and manuscripts, Raman spectroscopy is
able to identify also inks, in addition to pigments and dyes.
Nastova et al.[34] studied illuminated medieval old-Slavonic
manuscripts, and they found iron-gall inks, sometimes mixed
with carbon inks. The comparison of the pigments and inks
identified in these two analysed Slavonic manuscript showed a
good correspondence to the ones used in Western Europe in
the same period, except for green colors, obtained with indigo
and yellow ochre instead of indigo and orpiment, and for the
underlayer to the green pigment (yellow ochre instead of lead
white or lead tin yellow).
Due to the diffuse use of very brilliant, heavy metal-based
pigments, illuminated manuscripts and mural paintings are often
subjected to particular degradation processes. During the study
of a Medieval Cistercian 12th century manuscript, Muralha et al.[35]
found the transformation of white lead carbonate into black lead
sulfide galena. Blackening phenomena of metal-based pigments
are often present in polluted environments, as revealed by
Maguregui et al.[36] during a measurement campaign performed
in Pompeii by using portable Raman and XRF instrumentation;
red cinnabar (HgS) was found to degrade in metallic Hg and in
different Hg compounds; also hematite (a-Fe2O3), claimed to be a
stable pigment in most of the artists materials treatises, was found
to be reduced partially into magnetite (Fe3O4) under the action of
SO2 acid gas. However, blackening and chromatic alterations could
happen even in non-polluted environments, as reported by Aceto
et al.[37] in the analysis of painted meridians and religious wall
paintings present in the mountain hamlet of Ala di Stura, at
1080 m a.s.l. in the Lanzo Valleys (Italy); in this case, unstable lead
red and white pigments were transformed in black lead sulfide
and lead oxide (plattnerite), while the blue copper carbonate
azurite was transformed in a green hydroxychloride.
Paintings from the XIX-XX century have been performed using,
in addition to the traditional natural inorganic pigments, new
synthetic organic and inorganic materials. Up to now, the majority
of the published Raman studies are devoted to materials used in
ancient artworks, but the most recent materials still need an
adequate characterization. Casadio et al.[38] studied by Raman
spectroscopy a family of cobalt-based synthetic pigments; the
comparison of the spectra obtained on the reference materials with
the ones obtained on modern paintings allowed the identification
of cobalt titanate green in Jasper Johns palette and of cobalt
violet light and cobalt violet dark among the pigments used by
Copyright © 2012 John Wiley & Sons, Ltd.
J. Raman Spectrosc. 2012, 43, 1523–1528
Editorial
Pablo Picasso. Defeyt et al.[39] used various techniques to identify
the different crystalline phases of the largely diffuse blue dye copper phtalocyanine, in order to have a tool for a fine dating of modern paintings; Raman spectroscopy resulted the most efficient
technique for the detection of this dye in artists’ paints, but the
combination with XRD and IR spectroscopy is suggested to obtain
a precise identification of its crystalline structure.
Contemporary art is often made by ‘poor materials’, with complex
and largely variable composition, as in the case of pen drawings.
Sodo et al.[40] reported, for the first time, Raman spectra of ‘original’
and ‘laboratory’ drawings made by marker pens. The ‘original’ ones
are part of a collection of more than 500 original drawings of the
famous movie director Federico Fellini.
Ceramics, glasses and gemstones
J. Raman Spectrosc. 2012, 43, 1523–1528
Conclusion and future prospects
The 44 works included in this special issue are excellent examples
of the innovative applications of Raman spectroscopy from
prehistoric samples to present-day artifacts, representing the
current state of the art in the application of this vibrational
technique in Art and Archaeology. Some of them make use of other
non-destructive or micro-destructive instrumental techniques to
support the Raman information. Others highlight the possibilities
of field analysis, performed in a non-destructive way, to obtain
critical information for further studies on these Cultural Heritage artifacts. Others incorporate chemical modelling and/or chemometric
analysis to explain and interpret the presence of unexpected
materials together with the original ones. However, all of them
have in common the Raman information as the core of the works.
The high quality and the amount of spectroscopic information
from Raman and other techniques allow us to have a better
knowledge of the Art and Archaeological items we need to
analyse. However, to obtain the whole picture on the analysed
artifacts, we need to exchange our knowledge with other scientists
(spectroscopists, chemists, geologists, biologist, environmentalists,
etc.) and professionals in the side of Humanities (historians,
restorers, archaeologists, etc.) in an interdisciplinary approach.
The contribution of the people attending the RAA2011 Congress
to a research conducted in that collaborative way has been clearly
shown, and we hope to increase such cooperation in the works to
be presented in the forthcoming RAA2013 in Ljubljana, Slovenia.
Copyright © 2012 John Wiley & Sons, Ltd.
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Ceramics are very complex objects to study. The ceramic body
could be considered as a man-made metamorphic rock, containing
residuals of the raw materials (clays and other minerals), crystalline
and amorphous neo-formation phases, fluxing agents such as
feldspars, re-used fragments of older ceramics (chamotte) and
other inclusions. In addition, many different types of pigments were
used for decorations, and external coatings (glaze, engobe) are
often present. Such complex artifacts require a multi-technique
approach to perform the adequate characterization of original
and altered compounds. Up to six works are now discussed,
highlighting different aspects of such complex ceramic and glass
samples.
Sanchez Vizcaino et al.[41] made a combined use of micro-Raman
and energy dispersive X-ray microfluorescence (mEDXRF) to analyse
ceramic and glass vessel fragments found in the Iberian cemetery
of Tutugi (4th–3rd century BC, Galera, Granada, Spain), paying a
particular attention on the nature of pigments. The high Raman
signal usually obtained from heavy minerals and the ability of
Raman spectroscopy to discriminate between phases with very
similar composition, even within the same family (i.e. feldspars),
made this technique very effective in the study of the tempers of
ancient light-clay products.
Fintor and Gyalai[42] were able to discriminate, through microRaman analysis of the temper grains, Terra Sigillata samples coming
from different regions of North-Eastern Hungary. In particular, they
found that temper grains of samples from Pfaffenhofen and
Westerndorf contain more calcic minerals, including plagioclases
and heavy minerals (augite, diopside, actinolite, apatite and titanite)
while the ones from Rheinzabern contain mostly potassium
feldspars and only anatase and rutile as heavy minerals.
In case of large objects, too precious to be moved from the
museums, it is possible to use mobile equipments. Ferrer et al.[43]
used an optical fiber Raman system to investigate the composition
of yellow and orange colors of XVI and XVII centuries ceramics into
the ‘Museo de Cerámica de Barcelona’ (Spain). That work showed
how Raman spectroscopy is very effective in the detection of
ceramic pigments based on lead, tin and antimony, allowing to
discriminate among the complex family of ternary and quaternary yellow compounds used in Renaissance and Baroque
polychrome ceramics.
Zuluaga et al.[44] used a combination of micro-Raman, XRD and
SEM–EDX to differentiate between alkaline glazed and lead glazed
potteries, in the analysis of late medieval Christian and Muslin
pottery from Northern Spain. The glazes were discriminated by
Raman spectroscopy through the analysis of the Si–O bending and
stretching bands, in terms of the different SiO4 tetrahedra Qn units.
The glass structure and the variation of degree of polymerization as
a function of potassium content were studied by De Ferri et al.[45]
in medieval-like glass samples and compared with ancient K-based
glasses; the Raman study of the aging process of the glass samples
allowed to reveal the neo-formation of crystalline phases together
with the structural changes of the glass. Di Martino et al.[46] focused
their attention on rare inclusions in ancient glass mosaic tesserae
belonging to Daphni Monastery (Greece, XI century); the presence
of metallic silicon crystals embedded in the glass matrix supports
the hypothesis of local glass making in contrast with raw materials
supplied only from Middle East or Egypt.
Raman spectroscopy is widely used in gemology field, and three
works are included in this special issue. Giarola et al.[47] showed
some examples about the ability of this technique to gather
information on the nature and genesis of the gemstones by
analyzing the inclusions through a confocal Raman microscope;
they also showed how it is easy to unmask sophisticated fakes or
imitations such as a ‘doublet’, the classical assembled gemstones.
The use of some additional optics, such as L-shaped lens, allows
us to study gems mounted on artifacts or archaeological objects, as
it was shown by Karampelas et al.[48]; they studied the gems
adorning two chalices from the Benedictine Abbey of Einsiedeln
(Switzerland) in a completely non-invasive way. The use of three
different laser sources made possible the identification of all the
gemstones, even in case of strong fluorescence.
Even organic gemological materials can be studied by means
of Raman spectroscopy. Łydżba-Kopczyńska et al.[49] analysed
over 100 objects of unique amber jewelry, dated back to early
Iron Age, discovered in Domaslaw in Lower Silesia (Poland).
The comparison with reference materials from previously
selected amber deposits confirmed the Baltic origin for the
archeological jewelry.
Editorial
Acknowledgements
We are extremely grateful to the participants and institutions that
assisted in making the conference possible. In particular, we would
like to thank the University of Parma. Biblioteca Palatina as well as
the National Archaeological Museum of Parma are acknowledged.
The organizing committee expresses its thanks to the following
companies who supported also the conference: Renishaw,
Thermo-Fischer Scientific, HORIBA Jobin Yvon, Madatec Srl and
BWtech. J.M. Madariaga acknowledges the support of the UFI
Global Change and Heritage (ref. UPV/EHU-UFI11/26).
D. Bersania
J. M. Madariagab*
*
Correspondence to: Department of Analytical Chemistry, Faculty of
Science and Technology, University of the Basque Country,
P.O. Box 644, 48080 Bilbao, Spain
E-mail: juanmanuel.madariaga@ehu.es
a
Department of Physics and Earth Sciences, University of Parma, Parco
Area delle Scienze, 7/A, 43124 Parma, Italy
b
Department of Analytical Chemistry, Faculty of Science and Technology,
University of the Basque Country, P.O. Box 644, 48080 Bilbao, Spain
References
[1] H. G. M. Edwards, J. M. Chalmers (Eds), Raman Spectroscopy in
Archaeology and Art History, Royal Society of Chemistry, Cambridge, 2005.
[2] P. Vandenabeele, J. Raman Spectrosc. 2004, 35, 607.
[3] L. Bellot-Gurlet, S. Pages-Camagna, C. Coupry, J. Raman Spectrosc.
2006, 37, 962.
[4] P. Baraldi, A. Tinti, J. Raman Spectrosc. 2008, 39, 963.
[5] J. M. Madariaga, J. Raman Spectrosc. 2010, 41, 1389.
[6] P. H. Colomban, J. Raman Spectrosc. 2012, 43, 1529.
[7] W. Fremout, S. Saverwyns, J. Raman Spectrosc. 2012, 43, 1536.
[8] P. Vandenabeele, L. Moens, J. Raman Spectrosc. 2012, 43, 1545.
[9] E. Casanova-González, A. García-Bucio, J. L. Ruvalcaba-Sil, V.
Santos-Vasquez, B. Esquivel, T. Falcón, E. Arroyo, S. Zetina, M. L.
Roldán, C. Domingo, J. Raman Spectrosc. 2012, 43, 1551.
[10] A. Broggi, E. Petrucci, M. P. Bracciale, M. L. Santarelli, J. Raman Spectrosc.
2012, 43, 1560.
[11] M. Prencipe, J. Raman Spectrosc. 2012, 43, 1567.
[12] S. Potgieter-Vermaak, B. Horemans, W. Anaf, C. Cardell, R. Van Grieken,
J. Raman Spectrosc. 2012, 43, 1570.
[13] P. Ropret, T. Kosec, J. Raman Spectrosc. 2012, 43, 1578.
[14] T. Kosec, P. Ropret, A. Legat, J. Raman Spectrosc. 2012, 43, 1587.
[15] F. Ospitali, C. Chiavari, C. Martini, E. Bernardi, F. Passarini, L. Robbiola,
J. Raman Spectrosc. 2012, 43, 1596.
[16] C. Conti, I. Aliatis, C. Colombo, M. Greco, E. Possenti, M. Realini, C.
Castiglioni, G. Zerbi, J. Raman Spectrosc. 2012, 43, 1604.
[17] E. Joseph, A. Simon, R. Mazzeo, D. Job, M. Wörle, J. Raman Spectrosc.
2012, 43, 1612.
[18] V. Bongiorno, S. Campodonico, R. Caffara, P. Piccardo, M. M. Carnasciali,
J. Raman Spectrosc. 2012, 43, 1617.
[19] M. V. Cañamares, S. Sanchez-Cortes, S. Martinez-Ramírez, J. Raman
Spectrosc. 2012, 43, 1623.
[20] H. Morillas, M. Maguregui, O. Gomez-Laserna, J. Trebolazabala, J. M.
Madariaga, J. Raman Spectrosc. 2012, 43, 1630.
[21] S. Lahlil, M. Lebon, L. Beck, H. Rousselière, C. Vignaud, I. Reiche,
M. Menu, P. Paillet, F. Plassard, J. Raman Spectrosc. 2012, 43,
1637.
[22] A. Hernanz, J. M. Gavira-Vallejo, A. J. F. Ruiz-López, S. Martin, A.
Maroto-Valiente, R. de Balbín-Behrmann, M. Menéndez, J. J. AlcoleaGonzález, J. Raman Spectrosc. 2012, 43, 1644.
[23] V. Hernández, S. Jorge-Villar, C. Capel Ferrón, F. J. Medianero, J. Ramos,
G.-C. Weniger, S. Domínguez-Bella, J. Linstaedter, P. Cantalejo,
M. Espejo, J. J. Durán Valsero, J. Raman Spectrosc. 2012, 43, 1651.
[24] H. G. M. Edwards, E. M. A. Ali, S. O’Connor, J. Raman Spectrosc. 2012,
43, 1658.
[25] C. Lofrumento, A. Zoppi, M. Ricci, E. Cantisani, T. Fratini, J. Raman
Spectrosc. 2012, 43, 1663.
[26] E. P. Tomasini, E. B. Halac, M. Reinoso, E. J. Di Liscia, M. S. Maier,
J. Raman Spectrosc. 2012, 43, 1671.
[27] M. Irazola, M. Olivares, K. Castro, M. Maguregui, I. Martinez-Arkarazo,
J. M. Madariaga, J. Raman Spectrosc. 2012, 43, 1676.
[28] B. Minceva-Sukarova, L. Robeva Cukovska,
A. Lluveras-Tenario, A.
Andreotti, M. P. Colombini, I. Nastova, J. Raman Spectrosc. 2012, 43,
1685.
[29] E. Cazzanelli, E. Platania, G. De Santo, A. Fasanella, M. Castriota,
J. Raman Spectrosc. 2012, 43, 1694.
[30] L. Carvalho, S. Pessanha, A. Le Gac, T. Madeira, J.-L. Bruneel, J. Raman
Spectrosc. 2012, 43, 1699.
[31] J. J. González-Vidal, R. Perez-Pueyo, M. J. Soneira, S. Ruiz-Moreno,
J. Raman Spectrosc. 2012, 43, 1707.
[32] L. Burgio, A. Cesaratto, A. Derbyshire, J. Raman Spectrosc. 2012, 43,
1713.
[33] M. Aceto, P. Zannini, P. Baraldi, A. Agostino, G. Fenoglio, D. Bersani,
E. Canobbio, E. Schiavon, G. Zanichelli, A. De Pasquale, J. Raman
Spectrosc. 2012, 43, 1722.
[34] O. Grupce, I. Nastova, B. Minceva-Sukarova, S. Turan, M. Yaygingöl,
M. Ozcatal, V. Martinovska, J. Raman Spectrosc. 2012, 43, 1729.
[35] V. S. F. Muralha, C. Miguel, M. J. Melo, J. Raman Spectrosc. 2012, 43,
1737.
[36] M. Maguregui, U. Knuutinen, I. Martinez-Arkarazo, A. Giakoumaki,
K. Castro, J. M. Madariaga, J. Raman Spectrosc. 2012, 43, 1747.
[37] M. Aceto, G. Gatti, A. Agostino, G. Fenoglio, M. Varetto, G. Castagneri,
J. Raman Spectrosc. 2012, 43, 1754.
[38] F. Casadio, A. Bezúr, I. Fiedler, K. Muir, T. Trad, S. Maccagnola,
J. Raman Spectrosc. 2012, 43, 1761.
[39] C. Defeyt, P. Vandenabeele, B. Gilbert, J. Van Pevenage, R. Cloots,
D. Strivay, J. Raman Spectrosc. 2012, 43, 1772.
[40] A. Sodo, M. Bicchieri, M. Guiso, M. A. Ricci, G. Ricci, J. Raman Spectrosc.
2012, 43, 1781.
[41] A. Sánchez Vizcaíno, J. Tuñón López, M. Montejo Gámez, D. Parras
Guijarro, J. Raman Spectrosc. 2012, 43, 1788.
[42] K. Fintor, Z. Gyalai, J. Raman Spectrosc. 2012, 43, 1796.
[43] P. Ferrer, S. Ruiz-Moreno, A. López-Gil, M. C. Chillón, C. Sandalinas,
J. Raman Spectrosc. 2012, 43, 1805.
[44] M. Cruz Zuluaga, A. Alonso-Olazabal, M. Olivares, L. Ortega, X. Murelaga,
J. J. Bienes, A. Sarmiento, N. Etxebarria, J. Raman Spectrosc. 2012, 43,
1811.
[45] L. de Ferri, D. Bersani, P. H. Colomban, P. P. Lottici, G. Simon,
G. Vezzalini, J. Raman Spectrosc. 2012, 43, 1817.
[46] D. Di Martino, A. Galli, M. Martini, J. Raman Spectrosc. 2012, 43,
1824.
[47] M. Giarola, G. Mariotto, M. Barberio, D. Ajo, J. Raman Spectrosc. 2012,
43, 1828.
[48] S. Karampelas, M. Wörle, K. Hunger, H. Lanz, J. Raman Spectrosc.
2012, 43, 1833.
[49] B. Łydżba-Kopczyńska, B. Gediga, J. Chojcan, M. Sachańbinski,
J. Raman Spectrosc. 2012, 43, 1839.
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J. Raman Spectrosc. 2012, 43, 1523–1528