Next Article in Journal
Photoluminescence Modulation of Fluorophores Extracted from Water Hyacinth (Eichhornia crassipes) Biomass via a Hydrothermal Process
Previous Article in Journal
Effective Antioxidants for Stabilization of Chlorophyll Adsorbed on Silica Surface
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Colorants
Volume 4
Issue 4
10.3390/colorants4040031
colorants-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Material Analysis of 18th Century Polychrome Sacred Sculpture of Our Lady: Iconographic Impact and the Conservation and Restoration Process

by
Thiago Guimarães Costa
1,*,
Karen Kremer
1,
Fábio Andreas Richter
1,
Feik Amil de Campos Júnior
2 and
Leonardo Negri Furini
3
1
Laboratory of Materials, Atelier for Conservation and Restoration of Cultural Heritage, Santa Catarina State Culture Foundation, Florianópolis 88025-200, SC, Brazil
2
Department of Chemistry, Federal University of Santa Catarina (UFSC), Florianópolis 88040-900, SC, Brazil
3
Department of Physic, Federal University of Santa Catarina (UFSC), Florianópolis 88040-900, SC, Brazil
*
Author to whom correspondence should be addressed.
Colorants 2025, 4(4), 31; https://doi.org/10.3390/colorants4040031
Submission received: 18 August 2025 / Revised: 17 October 2025 / Accepted: 18 October 2025 / Published: 22 October 2025
Browse Figures
Versions Notes

Abstract

In this work, molecular and elemental spectroscopic analyses were carried out on the preparation base, the paintings, the repaintings, and the gilding of an 18th century sacred sculpture of Our Lady found on Anhatomirim Island, where the Santa Cruz fortress was built in 1739 in the state of Santa Catarina, southern Brazil. The preparation base of the sculpture was characterized as gypsum (calcium sulfate dihydrate, (CaSO4.2H2O) [µ-Raman, SEM-EDS], applied directly to the wooden support. The blue paint comprised a mixture of Prussian blue (Fe4[Fe(CN)6]3) and ultramarine (NaxAl6Si6O24Sx) [µ-Raman, FTIR, SEM-EDS]; hematite (Fe2O3) was identified in the brown paint [µ-Raman, SEM-EDS]; and the white paint consisted of lead white (2 PbCO3·Pb(OH)2) [µ-Raman, FTIR, SEM-EDS]. Repainted areas were identified by the presence of lithopone (ZnS + BaSO4) [µ-Raman, SEM-EDS, FTIR], likely resulting from later interventions. In the gilded areas, gold was identified along with traces of iron [SEM-EDS], indicating a lower-quality gilding compared to, for example, silver alloys. Lead white was also identified in the polychrome areas, where it served to produce different tones in the painting. FTIR analyses revealed traces of aged oil used as a binder in the older layers. Mineral oil was detected in some samples, which may indicate that wax was used as a protective layer on the sculpture. The results will assist professionals in the iconographic characterization of the sacred image of Our Lady and in the conservation and restoration processes based on the identified constituent materials.

1. Introduction

Faith in Our Lady is related to a set of Marian devotions, with various specific denominations, which are widely disseminated within the Catholic Church. In Brazil, folkloric and iconographic studies have revealed one hundred and twelve different Marian invocations [1]. This variety of names for the Saint often poses a challenge for the identification of her images and, consequently, for the development of conservation and restoration work appropriate to each one due to different iconographic characteristics and different materials that changed over the past years. The situation is aggravated by the chronic lack of information in Brazil about the origins of collections, especially those located in ancient repositories, archaeological surveys, or even those in daily use.
The image referred to in this article (Figure 1) was found on Anhatomirim Island, where the Santa Cruz fortress (Figure 2) was built in 1739. The fortress was part of the 18th century defensive system of Santa Catarina Island, which houses the capital of the state of the same name in southern Brazil. The fortress was active until the end of World War II, after which it underwent progressive deactivation until its abandonment, depredation, and eventual ruin in the late 1950s. Recognized by the Brazilian federal government as a historical heritage site, the fortress began receiving successive conservation and restoration interventions from the late 1960s onwards.
Anhatomirim Island, where the image was found, is one of the most important archaeological sites in the state of Santa Catarina and southern Brazil. It was through the construction of the fortress there that the Portuguese Empire consolidated its dominance in the region in the 18th century and encouraged the arrival of Portuguese immigrants who occupied Santa Catarina Island and the mainland, which strongly influenced its geographic boundaries and shaped its culture. This process also generated a specific material culture, often adapted to the region’s context, but about which there is a significant lack of information and studies that allow us to understand the techniques and products used in its material remains, especially the sculptures.
In the case of the sculpture described in this article, no documentary archives were located that could clarify its specific invocation, its author, the place of its construction, the period in which it was made, or the materials used. This situation was aggravated by the damage suffered by the image, which lost most of its upper limbs, hands, and forearms. The gestures made by these parts of the sculptures are key elements in identifying the different invocations of Our Lady. The lack of information about these elements prevented a proper restoration process of the image, which involves not only the lost limbs but also the colors of the sculpture’s various details, which are also conditioned by the saint’s different invocations.
The lack of further information about the sculpture, combined with the damage it sustained over time, has made investigations into its materiality crucial for its proper identification and conservation and restoration efforts. Identifying its timeframe and the statuette’s associated Marian invocation has direct implications for restoration efforts related to its painting and the image’s gestural expressions, given the damage it suffered, including the loss of hands and arms, as seen in Figure 1. Visually, a white primer can be observed on the wood, over which various polychromes—in blue, brown, and white—and gilding have been applied, some at the same level as the primer and others above it. Some white repainting can also be observed on the sculpture’s mantle and base.
Analytical techniques are employed to analyze the constituent materials of cultural heritage objects, including vibrational spectroscopy (FTIR and micro-Raman) and SEM-EDS for molecular and elemental characterization, respectively. In several works, these techniques were used in sculptures and paintings [2,3,4,5]. This work aims to characterize the materials used in the preparation base, polychromy, repainting, and gilding of sacred wooden sculptures. The results obtained can be used by historians to determine the name of the Saint and to assist professionals in the restoration process.

2. Experimental Section

2.1. Sample Collection

The samples were collected during the restoration process. Detached fragments corresponding to each color, gilding, and preparation base were collected for instrumental analysis. Table 1 summarizes the descriptions of each sample collected and the analyses performed to identify the materials.

2.2. FTIR Spectroscopy

FTIR spectra were collected on a Jasco FTIR-4100 spectrometer using an attenuated total reflectance (ATR) module. The samples were placed directly on a ZnSe crystal. The spectra were collected with 64 scans with 4 cm−1 resolution. The spectra were processed with a Spectra Manager Suite for FT/IR-X Series—Jasco Inc. software version 2.0.

2.3. Raman Spectroscopy

The measurements were performed on a Renishaw in Via Reflex Spectrometer System coupled with Confocal Optical Microscope and Confocal Microscope Raman spectrometer with CCD detector electrically cooled. The spectra were obtained under the following experimental conditions: measurements under 20× objectives, 785 nm laser (500 mW) and 1200 L/mm grating, 1–10 s exposure and 5–100 acquisitions variation directly in the WiRe 5.6 software. The standard for the pigments was obtained in the RRUFF™ Project [6] and Pigments Checker version 3.0 [7].

2.4. SEM-EDS

The micrographs with a magnification of 50–100× and the EDS spectra were obtained on a Phenom electron microscope (model Pro-X) (Thermo Fisher Scientific, Eindhoven, The Netherlands), coupled with an energy dispersive X-ray spectrometer, using an accelerating voltage of 15 kV with a backscattered electron detector (BSE) (Thermo Fisher Scientific, Eindhoven, The Netherlands). Elementary analysis was carried out with the 64 scans. All samples were directly fixed in the sample holder without any treatment.

3. Result and Discussion

3.1. FTIR Spectroscopy

The FTIR spectra of samples S1, S3, S4, S5, S6, along with details of the region between 1900 and 1600 cm−1 can be seen in Figure 3.
All the FTIR spectra showed bands related to a lipid binder. The characteristic signals of an oil can be observed in the regions between 2900–2850 cm−1 (νC-H, ν: stretching), 1735–1730 cm−1 (ester νC=O), 1100–1050 cm−1 (νC-O) and 715–720 cm−1 (δCH2, δ: bending). These signals were extensively reported in the literature [8,9,10,11,12,13,14]. Regarding the C=O stretching of the ester, it is possible to note in the enlarged region between 1700–1600 cm−1 a lower intensity in samples S1, S3, S4 and S5 compared to sample S6. The presence of bands between 1705 and 1712 cm−1 is also observed in samples S1–S5, attributed to the νC = O of carboxylic acids resulting from the hydrolysis and oxidative degradation of the triglycerides present in oil binder [15,16] Another interesting observation is that samples S1, S3 and S4 have a band in the region of 2955–2957 cm−1 attributed to the C-H3 antisymmetric stretching of the carbon chain and 1471 cm−1 and 1463 cm−1 related to δCH2, which can be attributed to a mineral wax used as a protective layer of the work, such as microcrystalline wax [17,18].
The spectrum of sample S6 shows an absence of bands attributed to the carbonyl of the carboxylic acid group. Thus, the triglyceride structure is better preserved when compared with the other paint samples. Therefore, this region may be attributed to a possible repainting in a more recent restoration process. Micro-Raman and EDS analyses revealed the presence of lithopone only in this sample, unlike the others that used lead white, confirming the suggestion that sample S6 is a more recent oil paint.
Regarding inorganic pigments, the sample S3 shows bands at 2088 cm−1 attributed to the νCN of the Prussian blue pigment [19] and 982 cm−1 assigned to the Si–O–Al stretching of the ultramarine pigment [20]. Sample S4 presents the following bands: 1110, 1682, 1622, 666 and 599 cm−1 attributed to the gypsum vibrational modes present in the preparation base [21]. The high intensity band at 1390 cm−1 in sample S5 corresponds to the CO32− stretching of lead white [22]. Finally, in sample S6 the bands at 1175, 1116 and 1075 cm−1 are attributed to the lithopone pigment [23]. The presence of these inorganic pigments corroborates the data obtained by µ-Raman and the elements found by SEM-EDS.

3.2. Raman Spectroscopy

The Raman spectra of samples S1, S3, S4, S5 and S6 can be seen in Figure 4, as well the standard references. In general, there is a good agreement between the samples and the standard patterns, confirming the composition of sculpture pigments.
In the spectrum of brown sample S1, the presence of the highest intensity bands at 222, 296, 402, and 610 cm−1 is attributed to the hematite pigment [24]. In blue sample S3, bands at 524, 712, 770, and 1314 cm−1 correspond to the pigment ultramarine [25] and bands at 2091 and 2150 cm−1 are assigned to the pigment Prussian blue [26], revealing a mixture of these two pigments used in the painting areas of this color. The sample S4, corresponding to the white of the preparation base, presents the main bands at 411, 491, 617, 665, 1008 and 1132 cm−1 which can be assigned to gypsum and calcium sulfate [27]. Also, a prominent band can be observed at 1085 cm−1 and assigned to calcium carbonate [28]. We can speculate that the presence this compound is related to an impurity or used in small quantities in some formulation to prepare the base. Sample S5, corresponding to the white pigment in the face of sculpture, presents the highest intensity bands at 410, 1050 and 1380 cm−1, indicating the presence of lead white [29]. Finally, sample S6, corresponding to the repainting areas on the head of the image, shows bands at 459, 616, 985 and 1138 cm−1 related to the lithophone pigment [30]. The results of the molecular analysis of the pigments corroborate the elements found in the SEM-EDS analyses presented and discussed in Section 3.3.

3.3. SEM-EDS

The EDS spectra of the six samples are shown in Figure 5. Elemental analysis corroborates with the data obtained through molecular analyses by Raman and FTIR spectroscopy regarding the characterization of the main pigments responsible for the sculpture’s polychromy. The brown color spectrum (S1 sample) shows the elements Fe, Ca, S, Pb, Si, and Al, with iron, aluminum, and silicon present in the earth pigment hematite, and traces of lead in the lead white used for lighter tones. The gilding (S2 sample) presents the elements Au, Fe, S, and Ca, with iron and gold present in the gold alloy. The blue paint (S3 sample) presents the elements Fe, Ca, K, S, Si, Al, and Na, with iron characteristic of Prussian blue and the elements Si, Al, Na, and S present in the ultramarine pigment.
The preparation base (S4 sample) presents the elements Ca and S corresponding to the gypsum. The white paint (S5 sample) of the carnation (neck and face) presents the elements Pb, Ca, Al and Si characteristic of lead white and the presence of clay composed of aluminum silicates, probably to achieve the darker shade, as can be seen in Figure 1.
The spectrum of areas containing repainting with white color above the old layers (S6 sample) contains the elements Zn, Ba, Ca, Pb, and S. The presence of Zn and Ba is characteristic of the lithopone pigment, composed of zinc sulfide and barium sulfate, a pigment distinct from the lead white found in samples of the oldest polychrome. The lithopone pigment was introduced into the arts after lead white [31], and the identification of the areas containing this pigment is possibly due to reintegration and restoration processes performed later on the paint. Figure 6 shows a micrograph of the repainting area S6 sample, where the difference in contrast between the areas retouched with lithopone and the areas containing the older lead white is visible. The sulfur and calcium observed in all samples are attributed to traces of the plaster preparation base, calcium sulfate.
Table 2 presents a summary of the main results obtained in this work.
The materials found and described in Table 2 corroborate analyses performed on sculptures from the same period. Regarding the preparation base, Oliveira et al. [30] observed the use of calcium sulfate in two polychrome sculptures with gilding dated to the 17th–18th centuries. It is worth noting that this technique was employed during the Portuguese Baroque period to obtain a stable polychromy ground [32,33].
Recently, Borges et al. [34] conducted iconographic studies and material analyses of sculptures representing Our Lady of Conception, dating from the 18th and 19th centuries. These were polychrome wooden sculptures with gilding and iconographic descriptions similar to those described in this work. The authors present the material analysis, and the results demonstrated that the preparation base was also made with calcium sulfate; the pigments used to create the light tones included lead white and zinc white, the browns were Fe-based ochre, and the blue regions exhibited the presence of Prussian blue. In this same work, the authors describe the presence of Au, Fe, and Pb in the gilding of one of the sculptures, possibly using the same technique found in the sculpture analyzed in this work. In this way, similar materials and techniques were found in our sculpture, corroborating the dating of the work and a possible attribution to a sculpture of Our Lady of Conception due to iconographic similarities with one of the sculptures analyzed by Borges et al. [34].
The materials characterized in samples S1–S5 can be attributed to the oldest found in the sculpture. Despite significant losses, the identification and understanding of these pigments, binders, gilding, and the presence of a protective layer, as well as their state of conservation, are important for future development of appropriate restoration methodologies and environmental storage conditions for this sculpture.
The wooden base of the sculpture is firm and show no apparent damage. However, it is suggested that future work include microtomography and radiography analyses of the image to verify the internal structure and determine whether there are any oxidized metal fixing pins that may need to be replaced. These techniques are widely described in the literature and aid in assessing the conservation status of wooden sculptures [32,33,34,35,36].

4. Conclusions

Spectroscopic and molecular analyses of the polychrome wooden sacred sculpture representing Our Lady revealed that the oldest layers of paint contain lead white (2PbCO3·Pb(OH)2) as a pigment used to paint the incarnation (face and neck) and to obtain different shades for the blue and brown paintings. The presence of Prussian blue (Fe4[Fe(CN)6]3) and ultramarine (NaxAl6Si6O24Sx) was detected in the blue painting, and hematite (Fe2O3) was identified in the brown painting. A primer containing gypsum (CaSO4·2H2O) was applied directly to the wooden base. Some repainted areas contained lithopone pigment and were attributed to possible later restorations that may have occurred over time. In the areas with gilding, the presence of gold and iron was identified.
FTIR analyses of the binder in polychromatic areas revealed the presence of aged oil, with little trace of fatty acid esters in the structure and a large amount of carboxylic acid, indicating an advanced hydrolysis process of the oil matrix. There are also traces of mineral oil, which can be attributed to a wax used as a protective coating. In the repainting areas containing lithopone, it was possible to identify that the oily structure was more intact, with a pronounced presence of fatty acid esters, meaning it was applied later. Through material and comparison with other studies, this sculpture may represent Our Lady of Conception.
It can be observed that the sculpture analyzed in this work presents several pictorial layer losses; however, regardless of the state of conservation, the recommendations for safeguarding the oldest materials detected in this work through the pictorial layers and gilding must be followed with the intention of preserving the sculptural details and the chemical analysis was crucial for this purpose.
The instrumental analyses were essential for characterizing the construction method of the sacred sculpture’s polychromy and gilding. The results obtained will assist professionals in the most precise iconographic characterization of the sacred image of Our Lady and in the conservation and restoration process based on the constituent materials found in this work.

Author Contributions

Conceptualization, K.K. and F.A.R.; methodology, T.G.C.; validation, T.G.C. and L.N.F.; formal analysis, T.G.C. and F.A.d.C.J.; investigation, T.G.C., F.A.R. and L.N.F.; resources, T.G.C.; data curation, K.K. and F.A.d.C.J.; writing—original draft preparation, T.G.C.; supervision, L.N.F. and T.G.C. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by Fundacao de Amparo a Pesquisa e Inovacao do Estado de Santa Catarina (FAPESC), Edital 15/2023 and Edital 21/2024, grant number Fapesc/2023TR001507.

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.

Acknowledgments

The authors would like to thank designer Moysés Lavagnoli da Silva for editing the scientific photographs, government of the State of Santa Catarina for the infrastructure and Fundacao de Amparo a Pesquisa e Inovacao do Estado de Santa Catarina (FAPESC), Edital 15/2023 and Edital 21/2024.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Megale, N.B.; Costa, N.M. As devoções portuguesa e espanhola na implantação do culto a Maria no Brasil. In Proceedings of the Congresso Internacional de História, Maringá, Brazil, 9–11 October 2017; pp. 1978–1986. Available online: http://www.cih.uem.br/anais/2017/trabalhos/4064.pdf (accessed on 16 December 2020).
  2. Poliszuk, A.; Ybarra, G. Analysis of Cultural Heritage Materials by Infrared Spectroscopy. In Infrared Spectroscopy: Theory; Developments and Applications Nova Science Publishers: Hauppauge, NY, USA, 2014; pp. 519–536. [Google Scholar]
  3. Retko, K.; Legan, L.; Kosel, J.; Ropret, P. Identification of iron gall inks, logwood inks, and their mixtures using Raman spectroscopy, supplemented by reflection and transmission infrared spectroscopy. Herit. Sci. 2024, 12, 212. [Google Scholar] [CrossRef]
  4. Falcone, F.; Cinosi, A.; Siviero, G.; Rosatelli, G. Innovative methodological approach integrating SEM-EDS and TXRF microanalysis for characterization in materials science: A perspective from cultural heritage studies. Spectrochim. Acta Part B At. Spectrosc. 2024, 218, 106980. [Google Scholar] [CrossRef]
  5. Costa, T.; Junior, A.; Meurer, L.; Barbosa, R.d.S.; Richter, F.; Beirao, F.; Micke, G.A.; Goncalves, S.; Szpoganicz, B.; Gonçalves, S.; et al. SEM-FEG-EDS, GC-MS, EPR and vibrational spectroscopy analysis of materials in baroque-style sculpture “our lady of sorrows” from garopaba, santacatarina, brazil. Int. J. Conserv. Sci. 2023, 14, 937–954. [Google Scholar] [CrossRef]
  6. RRUFF Sample Database. Available online: https://rruff.info/ (accessed on 10 May 2025).
  7. Caggiani, M.C.; Cosentino, A.; Mangone, A. Pigments Checker version 3.0, a handy set for conservation scientists: A free online Raman spectra database. Microchem. J. 2016, 129, 123–132. [Google Scholar] [CrossRef]
  8. de Viguerie, L.; Payard, P.A.; Portero, E.; Walter, P.; Cotte, M. The drying of linseed oil investigated by Fourier transform infrared spectroscopy: Historical recipes and influence of lead compounds. Prog. Org. Coat. 2016, 93, 46–60. [Google Scholar] [CrossRef]
  9. Mazzeo, R.; Prati, S.; Quaranta, M.; Joseph, E.; Kendix, E.; Galeotti, M. Attenuated total reflection micro FTIR characterization of pigment–binder interaction in reconstructed paint films. Anal. Bioanal. Chem. 2008, 392, 65–76. [Google Scholar] [CrossRef]
  10. Costa, T.G.; Ritcher, F.A.; Correia, M.D.d.M.; Escorteganha, M.R.; Santiago, A.G.; Gonçalves, S.; Spudeit, D.A.; Micke, G.A.; Miranda, F.S. Multi-technical analysis as a tool to investigate structural species in the “replica” of First Mass in Brazil painting by Sebastião Vieira Fernandes. J. Mol. Struct. 2016, 1120, 196–204. [Google Scholar] [CrossRef]
  11. Henderson, E.J.; Helwig, K.; Read, S.; Rosendahl, S. Infrared chemical mapping of degradation products in cross-sections from paintings and painted objects. Herit. Sci. 2019, 7, 71. [Google Scholar] [CrossRef]
  12. Morsch, S.; van Driel, B.A.; van den Berg, K.; Dik, J. Investigating the Photocatalytic Degradation of Oil Paint using ATR-IR and AFM-IR. ACS Appl. Mater. Interfaces 2017, 9, 10169–10179. [Google Scholar] [CrossRef]
  13. DePolo, G.; Iedema, P.; Shull, K.; Hermans, J. Comprehensive Characterization of Drying Oil Oxidation and Polymerization Using Time-Resolved Infrared Spectroscopy. Macromolecules 2024, 57, 8263–8276. [Google Scholar] [CrossRef] [PubMed]
  14. Banou, P.; Boyatzis, S.; Choulis, K.; Theodorakopoulos, C.; Alexopoulou, A. Oil Media on Paper: Investigating the Interaction of Cold-Pressed Linseed Oil with Paper Supports with FTIR Analysis. Polymers 2023, 15, 2567. [Google Scholar] [CrossRef] [PubMed]
  15. Lazzari, M.; Chiantore, O. Drying and oxidative degradation of linseed oil. Polym. Degrad. Stab. 1999, 65, 303–313. [Google Scholar] [CrossRef]
  16. Cairns, L.K.; Forbes, P.B.C. Insights into the yellowing of drying oils using fluorescence spectroscopy. Herit. Sci. 2020, 8, 59. [Google Scholar]
  17. Thickett, D.; Pretzel, B. FTIR surface analysis for conservation. Herit. Sci. 2020, 8, 5. [Google Scholar] [CrossRef]
  18. Missau, J.; da Rocha, J.G.; Dotto, G.L.; Bertuol, D.A.; Ceron, L.P.; Tanabe, E.H. Purification of crude wax using a filter medium modified with a nanofiber coating. Chem. Eng. Res. Des. 2018, 136, 734–743. [Google Scholar] [CrossRef]
  19. Parma, M.G.; Beraldo, H.; Mendes, I.C. Syntheses of Prussian Blue Pigment Following 18th-Century Methodologies: Factors Influencing Product Purity and Syntheses Yields. ACS Omega 2025, 10, 11375–11385. [Google Scholar] [CrossRef] [PubMed]
  20. Wang, H.; Zhang, S.; Hu, S.; Zhen, Z.; Gomez, M.A.; Yao, S. A systematic study of the synthesis conditions of blue and green ultramarine pigments via the reclamation of the industrial zeolite wastes and agricultural rice husks. Environ. Sci. Pollut. Res. 2020, 27, 10910–10924. [Google Scholar] [CrossRef]
  21. Gómez, B.A.; Parera, S.D.; Siracusano, G.; Maier, M.S. Integrated analytical techniques for the characterization of painting materials in two south american polychrome sculptures. Paint. Mater. South Am. Polychrome Sculpt. e-PS 2010, 7, 1–7. [Google Scholar]
  22. Vagnini, M.; Anselmi, C.; Vivani, R.; Sgamellotti, A. Non-invasive detection of lead carboxylates in oil paintings by in situ infrared spectroscopy: How far can we go? Spectrochim. Acta A Mol. Biomol. Spectrosc. 2023, 301, 122962. [Google Scholar] [CrossRef]
  23. Sánchez-Polo, A.; Briceño, S.; Jamett, A.; Galeas, S.; Campaña, O.; Guerrero, V.; Arroyo, C.R.; Debut, A.; Mowbray, D.J.; Zamora-Ledezma, C.; et al. An Archaeometric Characterizationof Ecuadorian Pottery. Sci. Rep. 2019, 9, 2642. [Google Scholar] [CrossRef] [PubMed]
  24. Jubb, A.M.; Allen, H.C. Vibrational Spectroscopic Characterization of Hematite, Maghemite, and Magnetite Thin Films. ACS Appl. Mater. Interfaces 2010, 2, 2804–2812. [Google Scholar] [CrossRef]
  25. Clark, R.J.H.; Franks, M.L. The resonance Raman spectrum of ultramarine blue. Chem. Phys. Lett. 1975, 34, 69–72. [Google Scholar] [CrossRef]
  26. Moretti, G.; Gervais, C. Raman spectroscopy of the photosensitive pigment Prussian blue. J. Raman Spectrosc. 2018, 49, 1198–1204. [Google Scholar] [CrossRef]
  27. Berenblut, B.J.; Dawson, P.; Wilkinson, G.R. The Raman spectrum of gypsum. Spectrochim. Acta A Mol. Spectrosc. 1971, 27, 1849–1863. [Google Scholar] [CrossRef]
  28. Harris, J.; Mey, I.; Hajir, M.; Mondeshki, M.; Wolf, S.E. Pseudomorphic transformation of amorphous calcium carbonate films follows spherulitic growth mechanisms and can give rise to crystal lattice tilting. CrystEngComm 2015, 17, 6831–6837. [Google Scholar] [CrossRef]
  29. Burrafato, G.; Calabrese, M.; Cosentino, A.; Gueli, A.M.; Troja, S.O.; Zuccarello, A. ColoRaman project: Raman and fluorescence spectroscopy of oil, tempera and fresco paint pigments. J. Raman Spectrosc. 2004, 35, 879–886. [Google Scholar] [CrossRef]
  30. Bellei, S.; Nevin, A.; Cesaratto, A.; Capogrosso, V.; Vezin, H.; Tokarski, C.; Valentini, G.; Comelli, D. Multianalytical Study of Historical Luminescent Lithopone for the Detection of Impurities and Trace Metal Ions. Anal. Chem. 2015, 87, 6049–6056. [Google Scholar] [CrossRef]
  31. Clark, R.J.H. Raman microscopy: Application to the identification of pigments on medieval manuscripts. Chem. Soc. Rev. 1995, 24, 187–196. [Google Scholar] [CrossRef]
  32. Oliveira, M.; Murta, E.; Dias, L.; Mirão, J.; Candeias, A. Gilding materials and techniques: Comparison between altarpieces and their sculptures—A case study. Conserv. Patrim. 2015, 22, 41–49. [Google Scholar] [CrossRef]
  33. Calza, C.; Oliveira, D.; Freitas, R.; Rocha, H.; Nascimento, J.; Lopes, R. Analysis of Sculptures Using XRF and X-Ray Radiography. Radiat. Phys. Chem. 2015, 116, 326–331. [Google Scholar] [CrossRef]
  34. Borges, R.M.S.P.; Cavalcante, J.E.; Franzi, I.V.N.S.; Paula, A.G.; Silva, M.; Sanches, F.; Gomes, R.A.F.; Bueno, R.; Machado, A.; dos Anjos, M.; et al. Evaluating Sculptures Depicting Our Lady of Conception Through the Use of X-Ray Techniques. X-Ray Spectrom. 2025. ahead of print. [Google Scholar] [CrossRef]
  35. Badde, A.; Illerhaus, B. Three Dimensional Computerized Microtomography in the Analysis of Sculpture. Scanning 2008, 30, 16–26. [Google Scholar] [CrossRef] [PubMed]
  36. Azeredo, S.R.; Oliveira, R.; Gusmão, E.; Anjos, M.; Sanches, F.; Lopes, R.; Oliveira, D. X-ray radiographic analysis of the two wooden sculptures of 18th century. Braz. J. Radiat. Sci. 2025, 12, 2766. [Google Scholar] [CrossRef]
Colorants 04 00031 g001
Figure 1. Sacred sculpture in polychrome wood with gilding representing the image of Our Lady. Dimensions: 425 × 178 × 135 mm. S1–S6 are the locations where the samples were collected.
Figure 1. Sacred sculpture in polychrome wood with gilding representing the image of Our Lady. Dimensions: 425 × 178 × 135 mm. S1–S6 are the locations where the samples were collected.
Colorants 04 00031 g001
Colorants 04 00031 g002
Figure 2. Location where the sacred sculpture was found. Coordinates: 27°25′35″ S, 48°33′53″ W.
Figure 2. Location where the sacred sculpture was found. Coordinates: 27°25′35″ S, 48°33′53″ W.
Colorants 04 00031 g002
Colorants 04 00031 g003
Figure 3. Infrared spectra of samples S1, S3, S4, S5, S6 and magnification in the region of 1600–1900 cm−1.
Figure 3. Infrared spectra of samples S1, S3, S4, S5, S6 and magnification in the region of 1600–1900 cm−1.
Colorants 04 00031 g003
Colorants 04 00031 g004
Figure 4. Raman spectra of samples S1, S3, S4, S5 and S6 with the respective pigment standards obtained from references [6,7].
Figure 4. Raman spectra of samples S1, S3, S4, S5 and S6 with the respective pigment standards obtained from references [6,7].
Colorants 04 00031 g004
Colorants 04 00031 g005
Figure 5. EDS spectra of samples S1–S6.
Figure 5. EDS spectra of samples S1–S6.
Colorants 04 00031 g005
Colorants 04 00031 g006
Figure 6. (a) Micrograph of the S6 sample; (b) region with repainting in red and (c) EDS spectrum of the repainting areas.
Figure 6. (a) Micrograph of the S6 sample; (b) region with repainting in red and (c) EDS spectrum of the repainting areas.
Colorants 04 00031 g006
Table 1. Description of collected samples and instrumental analyses performed.
Table 1. Description of collected samples and instrumental analyses performed.
SampleDescriptionAnalysis Performed
S1Brown from mantleSEM-EDS, Raman, FTIR
S2Gilding from mantleSEM-EDS
S3Blue from mantleSEM-EDS, Raman, FTIR
S4White preparation base *SEM-EDS, Raman, FTIR
S5White paint of the face and neckSEM-EDS, Raman, FTIR
S6White repainting from headSEM-EDS, Raman, FTIR
* The white in the preparation base was identified together with samples S1, S2, S3, and S5.
Table 2. Summary of results obtained by instrumental methods and materials detected in each sample.
Table 2. Summary of results obtained by instrumental methods and materials detected in each sample.
SampleEDSFTIR (cm−1)µ-Raman (cm−1)Conclusions
S1
Colorants 04 00031 i001		Fe, Ca, Pb, S, Al, Si2955, 2916, 2848, 1733w, 1705, 1464, 1377, 1250, 1164, 729, 719222, 296, 402, 610
(a)
Earth brown: Hematite (Fe2O3) + Al + Si
(b)
Traces of lead white (2PbCO3·Pb(OH)2) used for paint tone
(c)
Oily binder with a high degree of hydrolysis
(d)
Preparation base containing calcium sulfate (CaSO4)
(e)
Traces of mineral wax
S2
Colorants 04 00031 i002		Au, Fe, S, Ca--
(a)
Gold and Iron Alloy
(b)
Preparation base containing calcium sulfate dihydrate (CaSO4.2H2O)
S3
Colorants 04 00031 i003		Fe, Ca, K, S, Al, Si, Na2955, 2913, 2845, 2088, 1732w, 1700, 1463, 1411, 1356, 1251, 1166, 1073, 982, 800, 730, 718, 608524, 712, 770, 920, 1314 (ultramarine)–2091, 2150 (Prussian Blue)
(a)
Prussian Blue (Fe4[Fe(CN)6]3) and ultramarine (NaxAl6Si6O24Sx).
(b)
Oily binder with a high degree of hydrolysis
(c)
Preparation base containing calcium sulfate (CaSO4)
(d)
Traces of mineral wax
S4
Colorants 04 00031 i004		Ca, S3541, 3402, 2955, 2916, 2848, 1731w, 1701, 1682, 1622, 1461, 1402, 1110, 800, 731, 716, 666, 599411, 491, 617, 665, 1008, 1132 (1087–CaCO3)
(a)
Gypsum–calcium sulfate dihydrate (CaSO4.2H2O)
(b)
Traces of calcium carbonate
S5
Colorants 04 00031 i005		Ca, Pb, Al, Si2929, 2847,1730w, 1526, 1390, 1099, 1037, 678420, 1048, 1353
(a)
Lead white (2PbCO3·Pb(OH)2) used for paint tone
(b)
Trace of clays: Al + Si
(c)
Oily binder with a high degree of hydrolysis
(d)
Traces of mineral wax
S6
Colorants 04 00031 i006		Zn, Ba, Ca, Pb, S2933, 2856, 1730, 1406, 1235, 1175, 1116, 1075, 1001, 871, 635459, 616, 646, 985, 1052, 1138
(a)
Zinc sulfide and barium sulfate–lithopone (ZnS + BaSO4)
(b)
Traces of Lead white(2PbCO3·Pb(OH)2)
(c)
Preparation base containing calcium sulfate (CaSO4)
(d)
Oily binder with preserved ester bond
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Costa, T.G.; Kremer, K.; Richter, F.A.; de Campos Júnior, F.A.; Furini, L.N. Material Analysis of 18th Century Polychrome Sacred Sculpture of Our Lady: Iconographic Impact and the Conservation and Restoration Process. Colorants 2025, 4, 31. https://doi.org/10.3390/colorants4040031

AMA Style

Costa TG, Kremer K, Richter FA, de Campos Júnior FA, Furini LN. Material Analysis of 18th Century Polychrome Sacred Sculpture of Our Lady: Iconographic Impact and the Conservation and Restoration Process. Colorants. 2025; 4(4):31. https://doi.org/10.3390/colorants4040031

Chicago/Turabian Style

Costa, Thiago Guimarães, Karen Kremer, Fábio Andreas Richter, Feik Amil de Campos Júnior, and Leonardo Negri Furini. 2025. "Material Analysis of 18th Century Polychrome Sacred Sculpture of Our Lady: Iconographic Impact and the Conservation and Restoration Process" Colorants 4, no. 4: 31. https://doi.org/10.3390/colorants4040031

APA Style

Costa, T. G., Kremer, K., Richter, F. A., de Campos Júnior, F. A., & Furini, L. N. (2025). Material Analysis of 18th Century Polychrome Sacred Sculpture of Our Lady: Iconographic Impact and the Conservation and Restoration Process. Colorants, 4(4), 31. https://doi.org/10.3390/colorants4040031

Article Metrics

Back to TopTop