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Abstract Indoor investigations are commonly used to assess the causes and extent of damage to bronze artwork and cultural heritage items; however, these methods typically involve destructive sampling and outdoor bronze sculptures are typically heavy and large, hindering their transport. In this study, 16 contemporary bronze sculptures exposed to outdoor environments for a period exceeding 20 years were evaluated in-situ to develop a non-destructive prediction model that can identify types of corrosion and quantify the amount of corrosion on bronze sculptures that cannot be easily transported. The sculptures were classified into three groups according to their patina chromaticity, reflectivity, and chemical composition. The corrosion characteristics were found to be copper oxide and sulfide patinas. Chromaticity and reflectivity investigations revealed that the chemical composition changes of the patinas corresponded to the formation of corrosion products, thus showing a high potential for the identification of the type of corrosion. Portable XRF spectroscopy showed that the low error rate of Cu make its compositional behavior a good indicator in identifying the type of corrosion of sulfide and chloride patinas. Portable Raman spectroscopy was able to detect basic sulfides such as brochantite, antlerite, and cuprite. The corrosion types and corrosion products on the bronze sculptures could be identified using chromaticity and reflectivity, portable X-ray fluorescence, and portable Raman spectroscopy. The rapid insitu diagnosis of these corrosion attributes is expected to contribute to establishing conservation treatment plans in the future.

Indoor investigations are commonly used to assess the causes and extent of damage to bronze artwork and cultural heritage items; however, these methods typically involve destructive sampling and outdoor bronze sculptures are typically heavy and large, hindering their transport. In this study, 16 contemporary bronze sculptures exposed to outdoor environments for a period exceeding 20 years were evaluated in-situ to develop a non-destructive prediction model that can identify types of corrosion and quantify the amount of corrosion on bronze sculptures that cannot be easily transported. The sculptures were classified into three groups according to their patina chromaticity, reflectivity, and chemical composition. The corrosion characteristics were found to be copper oxide and sulfide patinas. Chromaticity and reflectivity investigations revealed that the chemical composition changes of the patinas corresponded to the formation of corrosion products, thus showing a high potential for the identification of the type of corrosion. Portable XRF spectroscopy showed that the low error rate of Cu make its compositional behavior a good indicator in identifying the type of corrosion of sulfide and chloride patinas. Portable Raman spectroscopy was able to detect basic sulfides such as brochantite, antlerite, and cuprite. The corrosion types and corrosion products on the bronze sculptures could be identified using chromaticity and reflectivity, portable X-ray fluorescence, and portable Raman spectroscopy. The rapid insitu diagnosis of these corrosion attributes is expected to contribute to establishing conservation treatment plans in the future. [ABSTRACT FROM AUTHOR]

The accurate identification of pigments is of principal relevance in the field of cultural heritage conservation and restoration practices. In this preliminary study, a first attempt to set up a procedure for accurate red pigment identification, based on the assessment of the correlations existing between visible reflectance spectrometry (vis-RS) and Raman data, is presented. The proposed approach involved the realization of a library consisting of data acquired on a set of 35 pure red historical pigments supplied by ©Kremer Pigmente. In particular, vis-RS data, collected through a Konica Minolta CM-2600d spectrophotometer, were registered, together with the position of the Extrema Points (E.P.s) encompassing both the maximum and minimum points of the first derivative of the % spectral reflectance factor (SRF%) curves. Portable Raman spectroscopy measurements were collected by a B&W Tek Inc. portable Raman spectrometer equipped with a 785 nm laser. For each tested pigment, the positions and relative intensities of the characteristic Raman peaks were considered. The library was then tested for the characterization of the red/reddish painted areas of the medieval wall painting located within The Norman Castle of Aci Castello (Catania, Italy), and was shown to be essential for the unambiguous identification of the pigment used. It is worth noting that this study represents the first novel attempt to establish a reliable and efficient methodology for pigment identification, offering promising prospects in reducing uncertainties and ambiguities arising from the application of a single stand-alone approach.

The accurate identification of pigments is of principal relevance in the field of cultural heritage conservation and restoration practices. In this preliminary study, a first attempt to set up a procedure for accurate red pigment identification, based on the assessment of the correlations existing between visible reflectance spectrometry (vis-RS) and Raman data, is presented. The proposed approach involved the realization of a library consisting of data acquired on a set of 35 pure red historical pigments supplied by ©Kremer Pigmente. In particular, vis-RS data, collected through a Konica Minolta CM-2600d spectrophotometer, were registered, together with the position of the Extrema Points (E.P.s) encompassing both the maximum and minimum points of the first derivative of the % spectral reflectance factor (SRF%) curves. Portable Raman spectroscopy measurements were collected by a B&W Tek Inc. portable Raman spectrometer equipped with a 785 nm laser. For each tested pigment, the positions and relative intensities of the characteristic Raman peaks were considered. The library was then tested for the characterization of the red/reddish painted areas of the medieval wall painting located within The Norman Castle of Aci Castello (Catania, Italy), and was shown to be essential for the unambiguous identification of the pigment used. It is worth noting that this study represents the first novel attempt to establish a reliable and efficient methodology for pigment identification, offering promising prospects in reducing uncertainties and ambiguities arising from the application of a single stand-alone approach. [ABSTRACT FROM AUTHOR]

Detection of explosives and their residues in real time is of paramount importance to homeland security and military. In real-time applications, the suspected materials may contain several chemical compounds making the detection even more challenging. We demonstrate a compact portable Raman spectroscopic tool for quantitative detection of constituent explosives in a binary mixture using machine learning. For the experiment, two samples were considered and mixed at different weight percentages:—1,3,5-trinitroperhydro-1,3,5-triazine (RDX) and ammonium nitrate (AN). Linear regression was employed to quantify the amount of RDX and AN. Regression analyses were conducted using both univariate and multivariate machine learning methods. The Raman spectra were analyzed with and without background correction. Further, various feature/variable selection strategies were explored to find out the best analysis protocol. Our analysis shows that the background correction of the spectra does not improve the accuracy. Among various feature selection techniques, multivariate analysis by considering the total spectra and features associated with only peaks as input gives better results than univariate analysis and multivariate analyses of other sub-spectra. The results demonstrate that Raman spectroscopy combined with machine learning can be used as a reliable, compact, and fast tool for the real-time investigation of explosive mixtures. [ABSTRACT FROM AUTHOR]

A collection of Hellenistic–Roman glyptics, kept at the Regional Archaeological Museum "Paolo Orsi" (Syracuse, Italy), was investigated in situ with portable Raman spectroscopy with the aim of assessing the viability of this approach, not only for the immediate identification of the gemstones but also for a more in‐depth successive data treatment. At the same time, a corroboration of the autoptic identification of the materials, both archeological and belonging to historical collections, was looked for in order to verify and potentially correct what reported in the museum catalogue. Actually, most of the identifications could be confirmed, the glyptics being mainly made of chalcedony. Other materials found were garnet, glass, and amber. The larger group of chalcedony Raman spectra was subjected to principal components analysis treatment that, after appropriate pretreatment, resulted successful in separating spectra with higher or lower contribution of the band due to the presence of moganite and SiOH bonds. The garnet spectra were instead subjected to quantitative study to identify the main end member. Both the quick identifications and the more detailed studies on chalcedonies and garnets were achieved thanks to the nondestructive and noninvasive investigation, directly in situ, with no sample preparation and minimal interference with the museum's activities. [ABSTRACT FROM AUTHOR]

This study presents a non-invasive in situ methodology based on the use of portable elemental (energy dispersive X-ray fluorescence spectroscopy, EDXRF) and molecular (Raman spectroscopy) spectroscopic-based instrumentation as a tool to obtain preliminary information to assist subsequent provenance studies of archaeological cinnabar pigments in the laboratory. In this work, six cinnabar mineral ores, extracted from the Almadén mining district and an original raw pigment coming from the Archaeological Park of Pompeii have been analyzed. As the detection capacities and spectral resolution of the portable instruments are usually poorer than the equivalent benchtop equipment, a comparative study of the in-situ and laboratory results was conducted. Afterward, chemometric data treatment was performed considering both the molecular and elemental information. According to the elemental results, it was not possible to find a strong concordance between the cinnabar ores and the pigment from Pompeii, suggesting the need for additional methodologies in the laboratory (isotope ratio analysis) to complete a proper provenance study. However, this approach was useful to classify the ores according to their mineralogical differences. Therefore, this methodology could be proposed as a useful tool to conduct a representative sampling of the cinnabar mineral ores to be considered in a provenance study of archaeological cinnabar pigments. [ABSTRACT FROM AUTHOR]

Non-invasive optical spectroscopical analyses were conducted on the three main walls of Alexander and Roxane’s Wedding Room in Villa Farnesina, Rome. The north and the east walls were frescoed by Sodoma in 1519. The decoration of the third wall was subsequent and neither the author nor the period is known. The north and east walls underwent various restorations, some even very invasive. For these reasons, the supposed remaining original parts of the two walls by Sodoma were studied and compared with the third one, aiming to obtain more information about its author and epoch. The results show the use of the same pigments for the three walls. In particular, the same yellow pigments including lead antimonate, the use of enamel blue with Bi impurities whose use is time-limited, and the use of a certain kind of purple hematite. The commonality in the pictorial technique also emerged, especially in the yellow parts, painted in the same way on each wall. This information, and documentary sources, reinforce the hypothesis that the third wall was decorated shortly after the death of Agostino Chigi by someone who was well-acquainted with the materials and techniques used by Sodoma for the other two walls.

Zeolites are present in numerous outcrops of volcanites of different ages in Sicily (Italy). Some of these outcrops are important because they constitute the ideal genesis conditions of some of these minerals, which represent geological indicators of chemical and geothermal gradients involved during their formation. For this purpose, a group of zeolites coming from areas of the Ionian coast and Palagonia village (Eastern Sicily) was investigated by means of Raman spectroscopy. In the geological record, these areas have been influenced by intense volcanic events that produced mineralization of hydrothermal origin. Sicilian zeolite samples were analysed in situ using different mobile Raman apparatus, directly on the outcrops of Aci Castello and the nearby Lachea Island, or in local collections where they are preserved. Some of these samples have been then analysed using laboratory micro‐Raman to compare the results and identify the zeolite types. The strength and weakness points of each instrument have been highlighted. Often, the Raman spectra of zeolites are affected by broad fluorescence, making them of difficult interpretation. However, satisfying results were obtained with portable devices, whose identifications were confirmed by micro‐Raman, discerning zeolites of different groups, such as analcime, chabazite, natrolite and phillipsite. The use of portable instruments has demonstrated the possibility to obtain identification of zeolites and related minerals both on site and in the laboratory, whose results match with the geological setting of the considered areas. [ABSTRACT FROM AUTHOR]

Tanzanite is the blue to violet‐blue variety of the sorosilicate zoisite; its colour is due to vanadium substitution of aluminium in the octahedral sites and is proved to appear after natural or artificial heating to approximately 500°C. Its colour makes it a highly appreciated gemstone, for this reason often imitated or thermally treated with the aim of enhancing its hue. Tanzanite loose gemstones are easily identified by classical gemmology methods that are not always applicable to mounted jewels. At the same time, zoisite Raman spectra are rarely reported in literature and never with a systematic approach. In this work, zoisite samples and cut tanzanite gemstones were considered, with the aim of filling this gap by addressing different methodological aspects. Namely, the orientational effects were investigated to explain the spectral variability, the photoluminescence bands were differentiated from the Raman signals using different excitation wavelengths, and the effectiveness of portable instrumentation in the correct identification of tanzanite was evaluated. The results are encouraging, showing that zoisite is revealed, notwithstanding orientational effects, by both portable and laboratory Raman instruments with comparable performances, opening the way to an effective identification of mounted tanzanite gemstones. Furthermore, the employ of different excitation wavelengths allowed to distinguish the photoluminescence bands with both categories of devices, thus identifying rare earth elements (REEs) likely associated with the mineral's genesis. [ABSTRACT FROM AUTHOR]

Non-invasive optical spectroscopical analyses were conducted on the three main walls of Alexander and Roxane's Wedding Room in Villa Farnesina, Rome. The north and the east walls were frescoed by Sodoma in 1519. The decoration of the third wall was subsequent and neither the author nor the period is known. The north and east walls underwent various restorations, some even very invasive. For these reasons, the supposed remaining original parts of the two walls by Sodoma were studied and compared with the third one, aiming to obtain more information about its author and epoch. The results show the use of the same pigments for the three walls. In particular, the same yellow pigments including lead antimonate, the use of enamel blue with Bi impurities whose use is time-limited, and the use of a certain kind of purple hematite. The commonality in the pictorial technique also emerged, especially in the yellow parts, painted in the same way on each wall. This information, and documentary sources, reinforce the hypothesis that the third wall was decorated shortly after the death of Agostino Chigi by someone who was well-acquainted with the materials and techniques used by Sodoma for the other two walls. [ABSTRACT FROM AUTHOR]

This study presents a non-invasive in situ methodology based on the use of portable elemental (energy dispersive X-ray fluorescence spectroscopy, EDXRF) and molecular (Raman spectroscopy) spectroscopic-based instrumentation as a tool to obtain preliminary information to assist subsequent provenance studies of archaeological cinnabar pigments in the laboratory. In this work, six cinnabar mineral ores, extracted from the Almadén mining district and an original raw pigment coming from the Archaeological Park of Pompeii have been analyzed. As the detection capacities and spectral resolution of the portable instruments are usually poorer than the equivalent benchtop equipment, a comparative study of the in-situ and laboratory results was conducted. Afterward, chemometric data treatment was performed considering both the molecular and elemental information. According to the elemental results, it was not possible to find a strong concordance between the cinnabar ores and the pigment from Pompeii, suggesting the need for additional methodologies in the laboratory (isotope ratio analysis) to complete a proper provenance study. However, this approach was useful to classify the ores according to their mineralogical differences. Therefore, this methodology could be proposed as a useful tool to conduct a representative sampling of the cinnabar mineral ores to be considered in a provenance study of archaeological cinnabar pigments.

[Display omitted] • Four indicators are used to monitor the quality of fresh-cut Chinese yam. • Portable Raman spectroscopy was used for dynamic monitoring of fresh-cut Chinese yam. • The changes in key indicators of fresh-cut Chinese yam can be predicted by Raman spectroscopy coupled with PLSR model. • The PLSR model effect for water index was relatively the best. • The PLSR model performances of all indicators at high temperature were better than those at low temperature. Portable Raman spectroscopy coupled with partial least squares regression (PLSR) model was performed for monitoring and predicting four quality indicators, moisture content, water activity, polysaccharide content and microbial content of the fresh-cut Chinese yam at different storage temperatures. The variations in the four key indicators were first depicted through a spider web diagram as the storage temperature changed. More importantly, the four key indicators can be accurately monitored and predicted through optimized PLSR models combining with Raman spectroscopy. Among all of the PLSR models for the four indicators, the regression model for moisture content was relatively the best. In addition, storage temperature played a significant role on the model performance of PLSR. The model performance for all indicators at room temperature and high temperature was better than the corresponding PLSR models at refrigeration and freezing conditions. Especially at 25 ℃, the R2 in the calibration set basically reached 0.9. These observations indicated that portable Raman spectroscopy, a simple and easy-to-use detection technique, can monitor and predict the multiple quality indicators of fresh-cut Chinese yam combined with effectively PLSR model, which would be conducive to their applications in food industry. [ABSTRACT FROM AUTHOR]

Plasters and mortars of the Church of the Annunciation (Tortorici, Sicily) were characterized, for the first time, both at the elemental and molecular levels, by means of portable X-ray fluorescence (XRF) and Raman spectroscopy, to achieve information on the “state of health” of the whole structure. The understanding of their degradation mechanisms and the identification of consequent degradation patterns can define the environmental factors responsible for interpreting the potential pathological forms that can impact the general building vulnerability. In this sense, the results obtained in this article provide relevant information to identify and address both the characterization of building materials and the fundamental causes of their deterioration. At the same time, if coupled with the attempt to supply a chronological order of the major restoration interventions carried out on the investigated site, they provide new insights to calibrate the models for building vulnerability studies.

An in situ archaeometrical campaign was organized in 2018 for the physicochemical analysis of the exceptional Mosaico de los Amores of the Cástulo archaeological site (Linares, Spain). Several mobile instruments were brought on the field to investigate the colourful tesserae of the mosaic. The main aim of the current research paper is the comparison of different mobile instruments and their applicability on measuring in open air environments. In this study, the comparison of four mobile Raman instruments, using different excitation lasers and technologies, is discussed. Three portable, the EZRaman‐I dual Raman analyser from TSI Inc. (USA), the i‐Raman® EX from BWTEK (USA), and the BWS445‐785S InnoRam™ Raman spectrometer from BWTEK (USA), and one handheld system, the Bravo Raman spectrometer from Bruker (Europe), are compared in terms of their characteristics, applicability, and performance when conducting non‐invasive and non‐destructive analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • We designed an innovative Raman spectroscopy system that enables rapid nondestructive detection of food adulteration. • We constructed the first quantitative analysis model for rice flour adulteration with Rongalite. • We propose an innovative model SARNet based on residual structure combined with autoencoder for real-time detection of Rongalite content based on Raman spectroscopy. Rice flour is a raw material for various foods and is used as a substitute for wheat flour. However, some merchants adulterate rice flour with the illegal additive Rongalite to extend the shelf life and earn illegal profits. Rongalite is highly carcinogenic, and ingestion of more than 10 g can even cause death. high-performance liquid chromatography (HPLC) and mass spectrometry (MS) are currently the main methods for detecting food adulteration, however, the existing methods have many limitations, complex operation, expensive instrumentation, etc. Raman spectroscopy has the advantages of convenience and non-destructive samples, but Raman spectroscopy can be affected by interference such as fluorescence background that affects detection, in addition to the problem of difficult quantitative analysis due to nonlinear bias. In this article, we used the preprocessing method of Savitzky-Golay smoothing filtering and VTPspline to improve the quality of the spectra and proposed the SARNet, which combines autoencoder and residual network to achieve the quantitative analysis of Rongalite content in rice flour. The new model combines a linear model with a nonlinear model, which can solve the nonlinear problem effectively. Experiments showed that the new SARNet model achieved state-of-the-art results, achieving the best R2 of 0.9703 and RMSEP of 0.0075. The lowest Rongalite concentration detected by the portable Raman spectrometer was 0.49%. In summary, the proposed method using portable Raman spectroscopy combined with machine learning has low detection bias and high accuracy, which can realize quantitative analyses of adulterated Rongalite in rice flour quickly. The method provides an accurate and nondestructive analytical tool in the field of food detection. [ABSTRACT FROM AUTHOR]

Raman spectroscopy is a label-free, non-destructive, non-invasive analytical tool that provides insight into the molecular composition of samples with minimum or no sample preparation. The increased availability of commercial portable Raman devices presents a potentially easy and convenient analytical solution for day-to-day analysis in laboratories and production lines. However, their performance for highly specific and sensitive analysis applications has not been extensively evaluated. This study performs a direct comparison of such a commercially available, portable Raman system, with a research grade Raman microscope system for the analysis of water content of Natural Deep Eutectic Solvents (NADES). NADES are renewable, biodegradable and easily tunable “green” solvents, outcompeting existing organic solvents for applications in extraction from biomass, biocatalysis, and nanoparticle synthesis. Water content in NADES is, however, a critical parameter, affecting their properties, optimal use and extraction efficiency. In the present study, portable Raman spectroscopy coupled with Partial Least Squares Regression (PLSR) is investigated for rapid determination of water content in NADES samples in situ, i.e., directly in glassware. Three NADES systems, namely Betaine Glycerol (BG), Choline Chloride Glycerol (CCG) and Glucose Glycerol (GG), containing a range of water concentrations between 0% (w/w) and 28.5% (w/w), were studied. The results are directly compared with previously published studies of the same systems, using a research grade Raman microscope. PLSR results demonstrate the reliability of the analysis, surrendering R2 values above 0.99. Root Mean Square Errors Prediction (RMSEP) of 0.6805%, 0.9859% and 1.2907% w/w were found for respectively unknown CCG, BG and GG samples using the portable device compared to 0.4715%, 0.3437% and 0.7409% w/w previously obtained by analysis in quartz cuvettes with a Raman confocal microscope. Despite the relatively higher values of RMSEP observed, the comparison of the percentage of relative errors in the predicted concentration highlights that, overall, the portable device delivers accuracy below 5%. Ultimately, it has been demonstrated that portable Raman spectroscopy enables accurate quantification of water in NADES directly through glass vials without the requirement for sample withdrawal. Such compact instruments provide solvent and consumable free analysis for rapid analysis directly in laboratories and for non-expert users. Portable Raman is a promising approach for high throughput monitoring of water content in NADES that can support the development of new analytical protocols in the field of green chemistry in research and development laboratories but also in the industry as a routine quality control tool.

Abstract There are multiple challenges in analysing pigments in historic watercolour paintings on paper, and typically non-invasive, in situ methods are required. Recent developments in portable analytical instrumentation have made this more accessible to heritage institutions, but many commercial systems are not optimised for the specific requirements of manuscripts and works on paper. This paper describes the successful use of Raman spectroscopy, X-ray fluorescence spectroscopy (XRF) and hyperspectral imaging to identify and map watercolour pigments used by the eighteenth century botanical illustrator, Ferdinand Bauer, and demystify the unusual colour code system found in his sketches. The value, delicate nature and large size of these paintings necessitated the use of using in situ, non-contact methods of analysis. A portable, bespoke Raman spectrometer specifically designed for analysing pigments from works on paper was used together with a bespoke portable Fibre optic reflectance spectrometer, portable X-Ray Fluorescence spectrometer and a hyperspectral imaging sensor. The results demonstrate that although there is a significant compromise between achieving good Raman spectroscopic results from artists’ pigments and using sufficiently low laser power densities so as not to cause damage to the pigments, good results could be obtained with this portable system, particularly when combined with XRF, fibre optic reflectance spectroscopy (FORS) and hyperspectral imaging. Eight pigments were identified unequivocally from 125 watercolour paintings analysed, suggesting that Bauer used a more traditional and more limited palette than previously considered, and that his palette changed significantly in his later paintings. Similar pigments identified by the authors on colour chart that was discovered in 1999 in Madrid and attributed to Bauer, add weight to the attribution of this chart to Bauer. The data provides a much deeper insight into Bauer’s colour annotations, and how he was able to achieve such an impressive degree of colour fidelity in his work.

Graphical abstract Abstract Raman spectroscopy has become an essential analytical technique for field detection and identification of illicit or dangerous materials such as explosives, but its main drawback is low signal intensity. This problem can be circumvented by using surface enhanced Raman spectroscopy (SERS), in which scattering signals increase significantly for analytes adsorbed onto or near nanostructured surfaces of the plasmonic materials. However, despite numerous studies, SERS has still not been widely used in real-world applications. The main goal of the studies describe herein was to investigate the possibility of detection of trace amounts of selected explosive materials on various commercial and non-commercial SERS substrates using portable Raman instruments. Our studies have shown that while portable systems suitable for SERS measurement of trace amounts of explosives are readily available, the problem remains in the selection of reliable and reproducible SERS substrates. Among five investigated SERS substrates only two, Klarite 312 and GaN-pillars allowed for trace analysis of all studied explosive materials. In both cases, detected concentrations of explosives ranged from single to hundreds of μg/cm2 depending on the explosive material and the Raman spectrometer used. Based on our findings, it could be concluded that the best SERS substrates for trace analysis of explosives are substrates with hot spots densely and evenly distributed over a whole active area of SERS substrate. [ABSTRACT FROM AUTHOR]

The decorated graves of Tarquinia are among the more important pre-Roman records of classical painting in the Mediterranean. Their monumental series of funereal paintings, dated between the seventh and second century B.C. faithfully reflect the Etruscan civilization, of which they form a unique source of knowledge. They also represent indirect evidence of Greek paintings almost completely lost. The main goal of this research is the identification of pigments in order to clarify the unknown aspects of the materials used and, therefore, to furnish fundamental information to plan suitable restoration and conservation. With this aim in mind, complementary non-destructive and in situ handheld X ray fluorescence and Raman spectrometry were carried out on the wall paintings of eight of the more important Tarquinia graves, allowing us to highlight the use, together with common pigments such as hematite, carbon, goethite and calcite, of the more precious malachite, Egyptian blue, lazurite and cinnabar in some of the more notable tombs probably commissioned by rich nobleman. Furthermore, the research evidenced that the routine of mixture of pigments to obtain particular hues was a common practice for Archaic Etruscan painters. In this context the use of lazurite and probably of Tyran purple added to others pigments in symbolic details, opens new questions. On the whole, the value of these pigments gives additional importance to the Etruscan Necropolis. Moreover, the results of this study will be useful for future restoration and conservation strategies. [ABSTRACT FROM AUTHOR]

Portable Raman spectroscopy is applied for the first time on rock art paintings from hunter-gatherers in three different provinces in Patagonia, Argentina (Neuquén, Río Negro and Chubut). Selected archaeological sites were examined, revealing the local 'palette' of the native population and, if possible, the technology used. Moreover, alteration products were investigated to obtain valuable information for a better conservation and preservation of these magnificent rock art paintings. During a single research campaign, 16 shelters and one cave were investigated, which makes this study as one of the most condensed expeditions on measuring rock art paintings. Here, we evaluate the use of our portable Raman instrument to analyse rock art paintings under extreme conditions in Patagonia, Argentina. Several improvements are proposed to maximize the quality of the research output in such condensed expeditions. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

There are multiple challenges in analysing pigments in historic watercolour paintings on paper, and typically non-invasive, in situ methods are required. Recent developments in portable analytical instrumentation have made this more accessible to heritage institutions, but many commercial systems are not optimised for the specific requirements of manuscripts and works on paper. This paper describes the successful use of Raman spectroscopy, X-ray fluorescence spectroscopy (XRF) and hyperspectral imaging to identify and map watercolour pigments used by the eighteenth century botanical illustrator, Ferdinand Bauer, and demystify the unusual colour code system found in his sketches. The value, delicate nature and large size of these paintings necessitated the use of using in situ, non-contact methods of analysis. A portable, bespoke Raman spectrometer specifically designed for analysing pigments from works on paper was used together with a bespoke portable Fibre optic reflectance spectrometer, portable X-Ray Fluorescence spectrometer and a hyperspectral imaging sensor. The results demonstrate that although there is a significant compromise between achieving good Raman spectroscopic results from artists' pigments and using sufficiently low laser power densities so as not to cause damage to the pigments, good results could be obtained with this portable system, particularly when combined with XRF, fibre optic reflectance spectroscopy (FORS) and hyperspectral imaging. Eight pigments were identified unequivocally from 125 watercolour paintings analysed, suggesting that Bauer used a more traditional and more limited palette than previously considered, and that his palette changed significantly in his later paintings. Similar pigments identified by the authors on colour chart that was discovered in 1999 in Madrid and attributed to Bauer, add weight to the attribution of this chart to Bauer. The data provides a much deeper insight into Bauer's colour annotations, and how he was able to achieve such an impressive degree of colour fidelity in his work. [ABSTRACT FROM AUTHOR]

This contribution deals with the application of non destructive techniques (NDTs) in the assessment and monitoring of the state of conservation of historical architectural surfaces, during and after restoration and maintenance interventions. The aim is to present the authors’ direct and in-situ experience with the applications of NDTs among noteworthy real case studies in relation to selected common types of decay. Thermal imaging, ultrasonic investigation, testing for the assessment of physicochemical properties, and Raman spectroscopy were all performed in order to address, diagnose, and monitor: detachments, loss of material coherence, discoloration, superficial deposits, and rising damp and moisture in several important Italian built heritage (e.g., the Ghirlandina Tower in Modena, the Sacra of San Michele near Turin, and the Narthex of Saint Mark’s Basilica in Venice). [ABSTRACT FROM PUBLISHER]

Ripening is one of the most important transformations that fruits and vegetables suffer, from an unripe to a ripe stage. In this study, it was followed up and analyzed the variations in the composition of tomato fruits at different ripening stages (green or unripe, orange or middle ripe, red or ripe and brown or overripe). The results obtained from the Raman measurements carried out showed a change in the composition of tomato fruits in the transit from green to brown. The analysis confirmed an increase of carotenoids from an unripe to a ripe stage of these fruits, being lycopene the characteristic carotenoid of the optimum ripe stage. The presence of chlorophyll and cuticular waxes decrease from the unripe to the ripe stage. Moreover, the relative intensity of phytofluene, a transition compound in the carotenoid biosynthetic pathway, is higher in the orange or middle ripening stage. The results obtained in-situ, without cutting and handling the tomato fruits, by means of a portable Raman spectrometer offered the same information that can be achieved using a more expensive and sophisticated confocal Raman microscope. [ABSTRACT FROM AUTHOR]

Extra virgin olive oil is produced through either a cold press procedure or a centrifugation with no thermal and chemical treatments and it is considered as the best quality oil under the category of olive oils. The superior properties of olive oil due to its rich in phenolic and antioxidant content and its contribution to prevent several health problems has increased the demand for olive oil over the years. Consequently, it is nowadays sold at remarkably higher price than regular vegetable oils in the market. Unfortunately, extra virgin olive oil (EVOO) has been adulterated with other cheap oils due to potential high commercial profit. Even though, there are methods available to detect the adulteration in EVOO (such as chromatographic methods and PCR), alternative simpler and faster methods are being studied. In this study, performance of portable Raman spectroscopy to quantify soybean oil (SO) adulteration [up to 25 % (w/w)] in EVOO has been evaluated. Partial Least Square Regression (PLSR) calibration models were developed and both internally (using cross-validation, leave-one-out approach) and externally (using an independent sample set) validated. The model gave standard error of prediction (SEP) of 1.34 % (w/w) SO in EVOO and correlation coefficient of prediction (rPred) of 0.99. Additionally, the residual predictive deviation (RPD) value calculated for the model was found to be 5.71, indicating that the model was considered as 'good' and could be used for routine analysis and quality control applications. [ABSTRACT FROM AUTHOR]

Perchlorate (ClO4−) contamination has received increased attention the past two decades because of health concerns from its impact on thyroid function coupled with its environmental ubiquity and persistence. Here we demonstrate the detection of ClO4− below micromolar (<1 × 10−6 moles l−1) levels using a portable Raman instrument integrated with novel elevated gold (Au) ellipse dimer nanoantenna surface enhanced Raman scattering (SERS) architectures. The ellipse dimer nanoantenna architectures demonstrate improved ClO4− detection limits over previously reported SERS substrates while maintaining good reproducibility. The impact of chloride (Cl−), nitrate (NO3−), and sulfate (SO42−) interferences on the detection efficiency is systematically evaluated; SO42− is found to exhibit the largest interference effect at low concentrations while at higher ion concentrations the interference effects among ions are similar. Additionally, ClO4− concentrations on the order of 1 mg l−1 are determined in groundwaters collected from an US Department of Defense Navy site demonstrating the applicability of these SERS architectures for the rapid, field detection of trace-level ClO4− contamination within complex environmental samples. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Raman spectroscopy is commonly used in chemistry to identify molecular structure. This technique is a nondestructive analysis and needs no sample preparation. Recently, Raman spectroscopy has been shown to be effective as a multipurpose analytical method for forensic applications. In the present study, blood identification and discrimination between human and nonhuman blood were performed by a portable Raman spectrometer, which can be used at a crime scene. To identify the blood and to discriminate between human and nonhuman blood, Raman spectra of bloodstains from 11 species (human, rat, mouse, cow, horse, sheep, pig, rabbit, cat, dog, and chicken) were taken using a portable Raman spectrometer. Raman peaks for blood (742, 1001, 1123, 1247, 1341, 1368, 1446, 1576, and 1619 cm) could be observed by the portable Raman spectrometer in all 11 species, and the human bloodstain could be distinguished from the nonhuman ones by using a principal component analysis. This analysis can be performed on a bloodstain sample of at least 3 months old. The portable Raman spectrometer can be used at a crime scene, and this analysis is useful for forensic examination. [ABSTRACT FROM AUTHOR]

Portable Raman spectroscopy has been used for the detection of the date-rape drug flunitrazepam in spiked beverages that may be involved in cases of drug-facilitated sexual assault. Solutions of flunitrazepam with different concentrations were prepared in water and for each beverage type. Although some bands attributable to the beverage matrix are present, they did not interfere with the identification of the drug. Definitive evidence for contamination of the spiked drink concerned can be acquired within 10 s. The data can be acquired in situ and sample extraction and/or preparation steps are unnecessary. The ability of portable Raman spectrometers to interrogate spiked alcoholic beverages with flunitrazepam has been demonstrated. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In archaeometry, the advantages of a combined use of Raman spectroscopy and X-ray fluorescence spectroscopy are extensively discussed for applications such as the analysis of paintings, manuscripts, pottery, etc. Here, we demonstrate for the first time the advantage of using both techniques for analysing glyptics. These engraved gemstones or glass materials were originally used as stamps, to identify the owner, for instance on letters, but also on wine vessels. For this research, a set of 64 glyptics (42 Roman glass specimens and 22 modern ones), belonging to the collection of the museum ‘Quinta das Cruzes’ in Funchal (Madeira, Portugal), was analysed with portable Raman spectroscopy and handheld X-ray fluorescence (hXRF). These techniques were also used to confirm the gemological identification of these precious objects and can give extra information about the glass composition. Raman spectroscopy identifies the molecular composition as well as on the crystalline phases present. On the other hand, hXRF results show that the antique Roman glass samples are characterised with low Pb and Sn levels and that the modern specimens can be discriminated in two groups: lead-based and non-lead-based ones. [ABSTRACT FROM AUTHOR]

Acts of terror and warfare threats are challenging tasks for defense agencies around the world and of growing importance to security conscious policy makers and the general public. Explosives and chemical warfare agents are two of the major concerns in this context, as illustrated by the recent Boston Marathon bombing and nerve gas attacks on civilians in the Middle East. To prevent such tragic disasters, security personnel must be able to find, identify and deactivate the threats at multiple locations and levels. This involves major technical and practical challenges, such as detection of ultra-low quantities of hazardous compounds at remote locations for anti-terror purposes and monitoring of environmental sanitation of dumped or left behind toxic substances and explosives. Surface-enhanced Raman scattering (SERS) is one of todays most interesting and rapidly developing methods for label-free ultrasensitive vibrational “fingerprinting” of a variety of molecular compounds. Performance highlights include attomolar detection of TNT and DNT explosives, a sensitivity that few, if any, other technique can compete with. Moreover, instrumentation needed for SERS analysis are becoming progressively better, smaller and cheaper, and can today be acquired for a retail price close to 10,000 US$. This contribution aims to give a comprehensive overview of SERS as a technique for detection of explosives and chemical threats. We discuss the prospects of SERS becoming a major tool for convenient in-situ threat identification and we summarize existing SERS detection methods and substrates with particular focus on ultra-sensitive real-time detection. General concepts, detection capabilities and perspectives are discussed in order to guide potential users of the technique for homeland security and anti-warfare purposes. [ABSTRACT FROM AUTHOR]

Bricks and mortar currently constitute one of the most important building materials used in the construction of most modern facades. The deterioration of these materials is caused primarily by the impact of numerous external stressors, while poor manufacturing quality, particularly of mortars, can also contribute to this process. In this work, the non-invasive Raman spectroscopy technique was used to identify the recently formed deterioration compounds (primarily sulfates and nitrates) in bricks, artificial stones, and joint mortars from detached houses in the Bilbao metropolitan area (Basque Country, North of Spain), as well as to investigate the deterioration processes taking place in these materials. Additionally, to confirm and in some cases complement the results obtained with Raman spectroscopy, SEM-EDS and XRD measurements were also carried out. [ABSTRACT FROM AUTHOR]

Direct identification of pigments in mediaeval illuminated manuscripts was one of the first applications of Raman spectroscopy in art and archaeology. In previous in situ analysis of handwritings, the equipment was typically provided with a single excitation source. In this work, a portable Raman spectrometer (EZRAMAN-I-DUAL Raman system) is introduced to characterise the pigments used in an important illuminated mediaeval manuscript, De Civitate Dei (Library in Bruges, Ms.106). Characteristics important for these in situ measurements were discussed. We introduce a set-up that allows stable positioning of the equipment and point out the advantage of the availability of two lasers, which are part of the instrument. Good performance of the introduced Raman spectrometer, to allow pigment identification in a short time, is proved. Finally, pigments such as lead white (2PbCO3 · Pb(OH)2), lead-tin yellow type I (Pb2SnO4), malachite (Cu2CO3(OH)2), mosaic gold (SnS2), vermillion (HgS), carbon black (C), red lead (Pb3O4) and azurite (Cu3(CO3)2(OH)2) could be identified. These pigments were often used in mediaeval artworks and contribute to the enrichment of information of the materials used by the illuminator. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This work presents the results of field Raman analyses, assisted by a hand-held energy dispersive X-ray fluorescence spectrometer, for the experimental determination of efflorescence from walls and wall paintings of two Pompeian houses, one with many luxurious decorative elements (House of Marcus Lucretius, Regio IX, Insula 3, House 5/24) and a more modest building (Regio IX, Insula 3, House 1-2). Both exposed and protected rooms were measured in different year seasons, spring (May 2010) and summer (September 2011 and 2012) and considering different orientations. Chemical attacks of acid gases (CO2, SO2 and NOx) on the original compounds of the mortars, biominerals formed by the biological colonizations as well as direct rain-wash of the newly formed salts can be considered the three most serious problems of the archaeological remains from Insula IX 3 of Pompeii. Also, infiltration waters from the ground contribute to such decay. The walls and wall paintings exposed to the rain-wash are the worst preserved, probably as a result of a continuous cycle of CO2, SO2 and NOx acid attack to the original carbonate materials, involving loss of plaster. This severe decay was not observed in the rooms covered by roofs although those walls affected by infiltration waters from the ground showed decaying because of the action of the efflorescence on the carbonate materials acting as the binder of the mural painting remains in the houses of Pompeii. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

[Display omitted] • We develop an efficient and accurate method applied to Raman spectroscopy to identify unknown ore mineral samples. • We constructed a specific multi-scale dilated convolutional attention network and trained it with an extensive Raman spectra database of minerals. • The function of each module and the explanations of the feature extraction in our CNN network were analyzed by the ablation experiments and the Grad-CAM algorithm. • The proposed novel approach that exploits the advantages of portable Raman spectroscopy and a deep learning method is promising for rapidly identifying ore mineral samples. Electron portable Raman spectroscopy tools for ore mineral identification are widely used in raw ore analysis and mineral process engineering. This paper demonstrates an extremely fast and accurate method for identifying unknown ore mineral samples by portable Raman spectroscopy from the RRUFF database. Resampling and background subtraction procedures are used to eliminate the influence of the Raman spectrometer and fluorescence scattering. For the complex mineral spectral classification task, a multi-scale dilated convolutional attention network is designed. In addition, to investigate the identification performance of our method, several machine learning and two basic deep learning models, including k -nearest neighbor (k -NN), support vector machine (SVM), random forest (RF), cosine similarity, extreme gradient boosting machine (XGBoost), Alexnet and ResNet 18, are also developed on the mineral spectra database and applied for mineral identification. Comparative studies show that our CNN network outperforms other models with state-of-the-art results, achieving a top-1 accuracy of 89.51% and a top-3 accuracy of 96.54%. The function of each module and the explanations of the feature extraction in our CNN network were analyzed by ablation experiments and the Grad-CAM algorithm. The identification of ore mineral samples also proves the outstanding performance of our method. In conclusion, the proposed novel approach that exploits the advantages of portable Raman spectroscopy and a deep learning method is promising for rapidly identifying ore mineral samples. [ABSTRACT FROM AUTHOR]

Plasters and mortars of the Church of the Annunciation (Tortorici, Sicily) were characterized, for the first time, both at the elemental and molecular levels, by means of portable X-ray fluorescence (XRF) and Raman spectroscopy, to achieve information on the "state of health" of the whole structure. The understanding of their degradation mechanisms and the identification of consequent degradation patterns can define the environmental factors responsible for interpreting the potential pathological forms that can impact the general building vulnerability. In this sense, the results obtained in this article provide relevant information to identify and address both the characterization of building materials and the fundamental causes of their deterioration. At the same time, if coupled with the attempt to supply a chronological order of the major restoration interventions carried out on the investigated site, they provide new insights to calibrate the models for building vulnerability studies. [ABSTRACT FROM AUTHOR]

Abstract: Tomato (Solanum lycopersicum) fruit samples, in two ripening stages, ripe (red) and unripe (green), collected from a cultivar in the North of Spain (Barrika, Basque Country), were analyzed directly, without any sample pretreatment, with two different Raman instruments (portable spectrometer coupled to a micro-videocamera and a confocal Raman microscope), using two different laser excitation wavelengths (514 and 785nm, only for the confocal microscope). The combined use of these laser excitation wavelengths allows obtaining, in a short period of time, the maximum spectral information about the main organic compounds present in this fruit. The major identified components of unripe tomatoes were cutin and cuticular waxes. On the other hand, the main components on ripe tomatoes were carotenes, polyphenoles and polysaccharides. Among the carotenes, it was possible to distinguish the presence of lycopene from β-carotene with the help of both excitation wavelengths, but specially using the 514nm one, which revealed specific overtones and combination tones of this type of carotene. [Copyright &y& Elsevier]

This work presents the results of field Raman analyses, assisted by a hand-held energy dispersive-X-ray fluorescence spectrometer, to experimentally determine the composition of compounds present in the walls and wall paintings of two Pompeian houses, one with many luxurious decorative elements (the House of Marcus Lucretius, Regio IX, Insula 3, House 5/24) and a more modest building (Regio IX, Insula 3, House 1-2). These houses were excavated 150 years ago, and the majority of the rooms have been exposed outdoors. The chemical attacks of the acid gases and the biological colonisation can be considered the most serious problems of the archaeological remains from Insula IX 3 of Pompeii. The walls and wall paintings exposed to the rain-wash are the worst preserved ones, probably due to a continuous cycle of SO2 attack to the original materials, involving loss of plaster. This severe decay was not observed in the rooms covered by roofs; in these last rooms, the most noticeable pathologies are the presence of high humidity in the walls and the elevated amount of efflorescences. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: In the real marketplace, providing high-quality olive oil is important from the perspective of both consumers and producers. Quality control should meet all requirements in the production process, from farm to packaging. The quality of olive oil can be affected by several factors, including agricultural techniques, seasonal conditions, farming systems, maturity, method and duration of storage, and process technology. The quality of oil produced also depends largely on the quality of the olives. In an enterprise aimed at producing high-quality oils, olives with defects (‘ground’; i.e., fallen to the ground) should be separated from healthy fruit (‘sound’; i.e., collected directly from the tree), because a very small portion of low-quality fruit can ruin the whole batch. The fruit falls partly because of its maturation process, but also because of pest and disease attack or weather conditions (strong wind). Fruit that has fallen to the ground can suffer a rapid deterioration in quality. Currently, the separation of fruits is based mainly on visual inspection or information provided by the farmer. These are not very reliable procedures. Methods using analytical parameters to characterize the oil, such as acidity and peroxide value, can be applied, but they require a lot of time and materials. Alternative techniques are therefore needed for the rapid and inexpensive discrimination of olives as part of a quality control strategy. The work described here aims to determine the potential of low-resolution Raman spectroscopy for the discrimination of olives before the oil processing stage in order to detect whether they have been collected directly from the tree (i.e., healthy fruit) or not. Low-resolution Raman spectroscopy was applied together with multivariate procedures to achieve this aim. PCA was used to find natural clusters in the data. Supervised classification methods were then applied: Soft Independent Modeling of Class Analogy (SIMCA), PLS Discriminate Analysis (PLS-DA) and K-nearest neighbors (KNN). The best results were obtained using the KNN method, with prediction abilities of 100% for ‘sound’ and 97% for ‘ground’ in an independent validation set. These results demonstrated the potential of a portable Raman instrument for detecting good quality olives before the oil processing stage, by developing models that could be applied before this stage, thus contributing to an overall improvement in quality control. [Copyright &y& Elsevier]

Abstract: Pharmaceutical counterfeiting has become a significant public health problem worldwide and new, rapid, user-friendly, reliable and inexpensive methods for drug quality screening are needed. This work illustrates the chemical characterization of genuine and fake artesunate antimalarial tablets by portable Raman spectroscopy and validation by FT-Raman spectroscopy and ambient mass spectrometry. The applicability of a compact and robust portable Raman spectrometer (TruScan™) for the in situ chemical identification of counterfeit tablets is reported. [Copyright &y& Elsevier]

Abstract: This article presents the “in situ” and totally non destructive investigation of a wall painting in Santa María de Lemoniz (Biscay, Basque Country, Spain) by Raman microprobe spectroscopy 14 years after its restoration. Although no sample was allowed to be taken, it has been possible to determine the original pigments in the artwork (vermilion, red iron oxide, yellow iron oxide, carbon black, lead white), as well as some degradation products (calcium oxalate dihydrate, anhydrite). For the first time, the mechanism for the transformation of malachite into copper basic sulphates has been ascertained by the integration of Raman data with thermodynamic speciation studies. Moreover, some remarks regarding the unsuitability of the past intervention procedure with regard to the chemical stability of the artwork are made. [Copyright &y& Elsevier]

This work reports the use of a portable Raman microprobe spectrometer for the analysis of bulk and decaying compounds in carbonaceous materials such as stones, mortars and wall paintings. The analysed stones include limestone, dolomite and carbonaceous sandstone, gypsum and calcium oxalate, both mono- and dihydrated, being the main inorganic degradation products detected. Mortars include bulk phases with pure gypsum, calcite and mixtures of both or with sand, soluble salts being the most important degradation products. The pigments detected in several wall paintings include Prussian blue, iron oxide red, iron oxide yellow, vermilion, carbon black and lead white. Three different decaying processes have been characterised in the mortars of the wall paintings: (a) a massive absorption of nitrates that reacted with calcium carbonate and promoted the unbinding of pigment grains, (b) the formation of black crusts in the vault of the presbytery and (c) the thermodecomposition of pigments due to a fire. [ABSTRACT FROM AUTHOR]

Raman spectroscopy is a label-free, non-destructive, non-invasive analytical tool that provides insight into the molecular composition of samples with minimum or no sample preparation. The increased availability of commercial portable Raman devices presents a potentially easy and convenient analytical solution for day-to-day analysis in laboratories and production lines. However, their performance for highly specific and sensitive analysis applications has not been extensively evaluated. This study performs a direct comparison of such a commercially available, portable Raman system, with a research grade Raman microscope system for the analysis of water content of Natural Deep Eutectic Solvents (NADES). NADES are renewable, biodegradable and easily tunable "green" solvents, outcompeting existing organic solvents for applications in extraction from biomass, biocatalysis, and nanoparticle synthesis. Water content in NADES is, however, a critical parameter, affecting their properties, optimal use and extraction efficiency. In the present study, portable Raman spectroscopy coupled with Partial Least Squares Regression (PLSR) is investigated for rapid determination of water content in NADES samples in situ, i.e., directly in glassware. Three NADES systems, namely Betaine Glycerol (BG), Choline Chloride Glycerol (CCG) and Glucose Glycerol (GG), containing a range of water concentrations between 0% (w/w) and 28.5% (w/w), were studied. The results are directly compared with previously published studies of the same systems, using a research grade Raman microscope. PLSR results demonstrate the reliability of the analysis, surrendering R2 values above 0.99. Root Mean Square Errors Prediction (RMSEP) of 0.6805%, 0.9859% and 1.2907% w/w were found for respectively unknown CCG, BG and GG samples using the portable device compared to 0.4715%, 0.3437% and 0.7409% w/w previously obtained by analysis in quartz cuvettes with a Raman confocal microscope. Despite the relatively higher values of RMSEP observed, the comparison of the percentage of relative errors in the predicted concentration highlights that, overall, the portable device delivers accuracy below 5%. Ultimately, it has been demonstrated that portable Raman spectroscopy enables accurate quantification of water in NADES directly through glass vials without the requirement for sample withdrawal. Such compact instruments provide solvent and consumable free analysis for rapid analysis directly in laboratories and for non-expert users. Portable Raman is a promising approach for high throughput monitoring of water content in NADES that can support the development of new analytical protocols in the field of green chemistry in research and development laboratories but also in the industry as a routine quality control tool. [ABSTRACT FROM AUTHOR]

• The in-situ nondestructive analysis was carried out on the three colored drawings of the Altar of Agriculture (Beijing, China) for the first time. • The pigments used in the three colored drawings are identified successfully. • Combined with the pigments used and the associated history, it is speculated that the three colored drawings were painted at different times. The in-situ measurement was carried out on the pigments used in the colored drawings in the Altar of Agriculture (Beijing, China) for the first time by portable Raman and ED-XRF spectrometers. Three kinds of colored drawings (the original drawing, the restored drawing, and the repainted drawing) located in Sacrificial Storehouse were studied. The information of the pigments, including red lead, white lead, indigo, carbon black, and atacamite were found in the original drawing, while Bright red β-naphthol, Sudan Ⅰ, chrome yellow, titanium dioxide, ultramarine blue, and phthalocyanine green were identified from the repainted drawing. Chrome yellow, ultramarine blue, and phthalocyanine green were used in the green and blue regions of the restored drawing. According to the application history of the pigments and the records of the Altar of Agriculture, the original colored drawing could be dated to the Qianlong period. The pigments used in restoration and repaint hadn't followed up the original drawing. The main reason is a lack of knowledge about the pigments used in the original painting. Hence, the information of the pigments used in these original drawings is of great guiding significance for the subsequent protection and restoration of the architectural drawings in Altar of Agriculture (Beijing, China). [ABSTRACT FROM AUTHOR]