Home Tracing the Alteration of Verdigris Pigment through Combined Raman Spectroscopy and X-ray Diffraction, Part II: Natural Ageing
Article
Licensed
Unlicensed Requires Authentication

Tracing the Alteration of Verdigris Pigment through Combined Raman Spectroscopy and X-ray Diffraction, Part II: Natural Ageing

  • Lynn B. Brostoff EMAIL logo , Cynthia Connelly Ryan and Isabella Black
Published/Copyright: November 24, 2020
Restaurator. International Journal for the Preservation of Library and Archival Material
From the journal Restaurator. International Journal for the Preservation of Library and Archival Material Volume 41 Issue 4

Abstract

This study explores the natural alteration of verdigris, both in the form of neutral verdigris (Cu(II) (CH3COO)2⋅H2O) and basic verdigris (Cu(II)x(CH3COO)y(OH)z ⋅nH2O), through combined Raman spectroscopy and X-ray diffraction investigation of samples created seven to eleven years prior to analysis. The naturally aged paint films of neutral or basic verdigris in gum arabic on paper and parchment provide insight into the pigment’s well-known instability relevant to historical works in aqueous media on maps, prints, books and manuscript materials. The latter historical application is an area that has received far less attention than alteration of verdigris in oil-based paint films. Findings shed new light on alternate pathways for conversion of neutral verdigris to basic verdigris, including the formation of a previously unknown form of verdigris and amorphous material on alkaline paper substrates. Additionally, we demonstrate for the first time that copper hydroxyl chlorides can form in situ from neutral verdigris, in this case on parchment that has a chlorine-rich surface. These results advance our understanding of neutral verdigris alteration, and complement results from our prior artificial ageing study. Both studies point to neutral verdigris as the historically more important form throughout its heyday. Improved understanding of neutral verdigris instability and its alteration pathways are critical for confident identification of the pigment in historical works, leading to better risk assessment of collections of verdigris-containing heritage, such as maps.

Keywords: natural ageing; Raman spectroscopy; verdigris; X-ray diffraction
Corresponding author: Lynn B. Brostoff, Preservation Research and Testing Division, Preservation Directorate, Library of Congress, 101 Independence Ave. SE, Washington, DC20540, USA, E-mail:

Acknowledgments

The authors would like thank the following for their valuable assistance: Sylvia Albro, John Bertonaschi, Dan DeSimone, Heather Wanser, Susan Peckham, Yasmeen Khan, Eliza Spaulding, Gwenaelle Kavich, Alessa Gambardella, Cheryl Porter, Sebastian Bette, Eric Monroe and Fenella France.

Appendix

Materials and Methods

XRD patterns were recorded with a Rigaku D-Max Rapid µDiffractometer using Cu Kα radiation, a large area image plate detector, 40 kV and 30 mA power, a 0.3 mm collimator, 0° ω geometry, and 360° φ rotation. Samples were scraped from the substrates and mounted onto a sharpened wooden stick without adhesive; in the case of 2014 model samples, red mounting wax (Hampton Research HR00-819) was used. Spectral integration was performed with Rigaku 2DP software (version 1.0.3.4). Spectral manipulation such as peak pick, normalization, baseline subtraction, and searching in the 2011 ICDD databases was performed using Rigaku PDXL 2 software (version 2.1.3.6).

Raman spectra of multiple grains in each sample shown in this study were obtained using a Renishaw inVia Raman system outfitted with a Leica DM2500 microscope, Rayleigh notch filters, and a CCD detector. Spectra were taken with either a 514 nm Ar+ laser and 2400 l/mm grating, or a 785 nm diode laser and 1200 l/mm grating. Calibration was performed using the 520.5 cm−1 line of silicon. Spectra were collected using a 50x objective and neutral density filters to keep power at sample ≤0.6 mW, typically for 60–180 s exposures. Spectral manipulation included minimal smoothing but no baseline corrections using WiRE 4 software.

Ca, K, and Fe content in substrates was measured semi-quantitatively using a Bruker Tracer III-IV SDD X-ray fluorescence spectrometer with a Rh anode, 0.001 mm Ti filter, and vacuum pumping. Tube settings were 15 kV and 55 µA, and 40 kV and 20 µA, with 180 s exposures. Concentration was determined according to partial least squares regression line calibrations from a series of lab-made metal-doped Whatman No. 1 and historical reference papers for which S, Cl, K, Ca, and Fe content was determined by inductively coupled plasma mass spectrometry (ICP-MS) conducted at the University of Missouri. Details of the method can be found in Brostoff (2016). S, Cl, and other elemental content was estimated as major, minor or trace compared to XRF raw spectra of other papers and ICP-MS values. Substrate pH range was estimated with a commercial pH pen.

Material Sources

Material sources for 2003 workshop samples were as stated by the owners and listed in Table 2, and as described in section 2.1 above. Materials used in the 2013 and 2014 samples were: 1) Whatman No. 1 filter paper, Fisher Scientific, USA; 2) University of Iowa (UI) handmade, gelatin-sized, buffered rag paper (∼15,000–18,000 ppm Ca), as determined by X-ray fluorescence spectroscopy. Gum arabic powder (Acros Organics) was prepared as a stock solution in deionized water at 2 g/10 ml. Neutral verdigris was purchased from Kremer Pigments, L. Cornelissen & Son, and Sinopia Pigments, and also made in-house as described in section 2.1. BV1 was synthesized according to Rahn-Koltermann et al. (1991), as also followed in Scott (2002), recipe 11. Details may be found in Brostoff and Connelly Ryan (2020).

Figure A-1: XRD pattern (baseline subtracted) of lab-synthetized BV1 paint film in gum arabic on Whatman No. 1 paper, no artificial ageing, showing ICDD PDF reference matches (blue lines) for copper acetate hydroxide hydrate (BV1), PDF #00-058-0183 and #00-050-0407. Note that the figure crops the maximum of the 100% peak near 2-theta = 9.48° (d = 9.34 Å) in order to better show smaller peaks, which are about 18% of the latter peak.
Figure A-1:

XRD pattern (baseline subtracted) of lab-synthetized BV1 paint film in gum arabic on Whatman No. 1 paper, no artificial ageing, showing ICDD PDF reference matches (blue lines) for copper acetate hydroxide hydrate (BV1), PDF #00-058-0183 and #00-050-0407. Note that the figure crops the maximum of the 100% peak near 2-theta = 9.48° (d = 9.34 Å) in order to better show smaller peaks, which are about 18% of the latter peak.

Figure A-2: XRD patterns (baseline subtracted) obtained from NV reference powders: (A) bought from L. Cornelissen & Son; (B) synthesized from white vinegar and a copper sheet at room temperature; and (C) synthesized from white vinegar and a copper sheet at 85 °C. Reference patterns (D) and (E) from ICDD PDF database. Note that results indicate that sample (C) contains a minor amount of basic verdigris.
Figure A-2:

XRD patterns (baseline subtracted) obtained from NV reference powders: (A) bought from L. Cornelissen & Son; (B) synthesized from white vinegar and a copper sheet at room temperature; and (C) synthesized from white vinegar and a copper sheet at 85 °C. Reference patterns (D) and (E) from ICDD PDF database. Note that results indicate that sample (C) contains a minor amount of basic verdigris.

Figure A-3: Photomicrographs showing details of a thin commercial NV verdigris paint film (left) and thick/thin homemade verdigris paint film (right) in gum arabic on Roselle drawing paper after ∼11 years natural ageing (see Figure 1, bottom row, middle).
Figure A-3:

Photomicrographs showing details of a thin commercial NV verdigris paint film (left) and thick/thin homemade verdigris paint film (right) in gum arabic on Roselle drawing paper after ∼11 years natural ageing (see Figure 1, bottom row, middle).

Figure A-4: XRD sample patterns (baseline subtracted) of:(A) NV-W0a and (B) NV-W0b, NV paint films in gum arabic on Whatman No. 1 filter paper after ∼7 years natural ageing; and (C) wood mount and wax blank (without sample). The diffraction patterns from A and B show peaks that arise only from the mount/wax, and therefore lack of evidence for crystallinity. Samples A and B were positioned in the beam so that diffraction from the mount was minimized, resulting in decreased detection of mount peaks.
Figure A-4:

XRD sample patterns (baseline subtracted) of:(A) NV-W0a and (B) NV-W0b, NV paint films in gum arabic on Whatman No. 1 filter paper after ∼7 years natural ageing; and (C) wood mount and wax blank (without sample). The diffraction patterns from A and B show peaks that arise only from the mount/wax, and therefore lack of evidence for crystallinity. Samples A and B were positioned in the beam so that diffraction from the mount was minimized, resulting in decreased detection of mount peaks.

Figure A-5: Photomicrographs showing comparison of commercial NV paint film after ∼11 years of natural ageing (top) painted fairly thickly, and (bottom) painted very thinly on UI rag paper. The thick paint film (see Fig. 1, top row, right) contains clusters of particles on the order of hundreds of microns; the particles at the surface have turned green, while particles beneath this layer retain their teal-blue colour. The film on the bottom (see Figure 1, top row, left) is extremely thin, tinting the paper fibers pale green and showing scattered green particles on the order of tenths of microns; some particles here appear to be contaminants from other pigments.
Figure A-5:

Photomicrographs showing comparison of commercial NV paint film after ∼11 years of natural ageing (top) painted fairly thickly, and (bottom) painted very thinly on UI rag paper. The thick paint film (see Fig. 1, top row, right) contains clusters of particles on the order of hundreds of microns; the particles at the surface have turned green, while particles beneath this layer retain their teal-blue colour. The film on the bottom (see Figure 1, top row, left) is extremely thin, tinting the paper fibers pale green and showing scattered green particles on the order of tenths of microns; some particles here appear to be contaminants from other pigments.

Figure A-6: Additional Raman spectra (514 nm excitation) of commercial NV paint films in gum arabic from 2003 workshop samples after ∼11 years of natural ageing on various alkaline paper substrates, as follows: (A) on Fabriano paper, (B) on Stonehenge paper, (C) on Permalife paper, (D) on UI rag paper (thin film), (E) on UI rag paper (thick film, and (F) on Hahnemühle Bugra Bütten laid paper. Dotted lines show peaks characteristic of BVX. Power at the samples was 0.05 – 0.5 mW.
Figure A-6:

Additional Raman spectra (514 nm excitation) of commercial NV paint films in gum arabic from 2003 workshop samples after ∼11 years of natural ageing on various alkaline paper substrates, as follows: (A) on Fabriano paper, (B) on Stonehenge paper, (C) on Permalife paper, (D) on UI rag paper (thin film), (E) on UI rag paper (thick film, and (F) on Hahnemühle Bugra Bütten laid paper. Dotted lines show peaks characteristic of BVX. Power at the samples was 0.05 – 0.5 mW.

References

Bette, S., R. Kremer, G. Eggert, C. Tang, and R. Dinnebier. 2017. “On Verdigris, Part I: Synthesis, Crystal Structure Solution and Characterization of the 1-2-0 Phase (Cu3(CH3COO)2(OH)4.” Dalton Transactions 46: 14847–58, https://doi.org/10.1039/c7dt03288a.Search in Google Scholar

Bette, S., R. Kremer, G. Eggert, and R. Dinnebier. 2018. “On Verdigris, Part II: Synthesis of the 2-1-5 Phase (Cu3(CH3COO)4(OH)2-5H2O by Long-Term Crystallisation from Aqueous Solution at Room Temperature.” Dalton Transactions 47: 8209–20, https://doi.org/10.1039/c8dt01758a.Search in Google Scholar

Banik, G., and J. Ponahlo. 1982/1983. “Some Aspects of Degradation Phenomena of Paper Caused by Green Copper-Containing Pigments.” The Paper Conservator 7: 3–7, https://doi.org/10.1080/03094227.1982.9638442.Search in Google Scholar

Benhamou, R. 1984. “Verdigris and the Entrepreneuse.” Technology and Culture 25 (2): 171–81, https://doi.org/10.2307/3104711.Search in Google Scholar

Brostoff, L., S. Albro, J. Bertonaschi, and E. Spaulding. 2011. “The Relationship between Inherent Material Evidence in Cultural Heritage and Preservation Treatment Planning: Solving the Ptolemy Puzzle, Part II”, Book and Paper Group Annual 30, 29–33. Washington, DC: American Institute for the Conservation of Historic and Artistic Works.Search in Google Scholar

Brostoff, L., and C. Connelly Ryan. 2020. “Tracing the Alteration of Verdigris Pigment through Combined Raman Spectroscopy and X-Ray Diffraction, Part I.” Restaurator 45 (1): 3–30, https://doi.org/10.1515/res-2019-0007.Search in Google Scholar

Borshch, N. A., A. A. Davidenko, and A. N. Efremova. 2019. “Dependence of the Solubility of Basic Copper Acetate on the Concentration of the Solution and the pH of the Suspension.” Russian Journal of Physical Chemistry A 93 (9): 1733–6, https://doi.org/10.1134/s0036024419080053.Search in Google Scholar

Brostoff, L. 2016. “Appendix B: Determination of Metal Content in Fabriano Paper Used in Early Italian Printed Books.” In Sylvia Rogers Albro, Fabriano, City of Medieval and Renaissance Papermaking. Washington, DC: Oak Knoll Press with the Library of Congress.Search in Google Scholar

Buse, J., V. Otero, and M. J. Melo. 2019. “New Insights into Synthetic Copper Greens: the Search for Specific Signatures by Raman and Infrared Spectroscopy for their Characterization in Medieval Artworks.” Heritage 2 (2): 1614–29, https://doi.org/10.3390/heritage2020099.Search in Google Scholar

Caballol, R., J. M. Poblet, and J. P. Sarasa. 1988. “Unimolecular Reactions of the Enolic Tautomer Ionized Acetic Acid in the Gas Phase: an ab initio and RRKM Study.” Journal of Physical Chemistry 92 (12): 3336–41, https://doi.org/10.1021/j100323a007.Search in Google Scholar

Castro, K., S. Pessanha, N. Proietti, E. Princi, D. Capitani, M. L. Carvalho, and J. M. Madariaga. 2008. “Noninvasive and Nondestructive NMR, Raman and XRF Analysis of a Blaeu Coloured Map from the Seventeenth Century.” Analytical and Bioanalytical Chemistry 391: 433–41, https://doi.org/10.1007/s00216-008-2001-4.Search in Google Scholar

Cennini, C. 1960. The Craftsman’s Handbook “Il Libro dell’Arte.” D. V. Thompson, Jr. (trans.), 33 New York: Dover Publications, Inc.Search in Google Scholar

Chaplin, T. D., R. J. H. Clark, and D. A. Scott. 2006. “Study by Raman Microscopy of Nine Variants of the Blue-Green Pigment Verdigris.” Journal of Raman Spectroscopy 37: 223–9, https://doi.org/10.1002/jrs.1469.Search in Google Scholar

Clarke, M. 2011. Medieval Painters’ Materials and Techniques: The Montpellier Liber Diversarum Arcium. London: Archetype.Search in Google Scholar

De la Roja, J. M., V. G. Baonza, and M. San Andres. 2007. “Application of Raman Microscopy to the Characterization of Different Verdigris Variants obtained using Recipes from Old Treatises.” Spectrochimica Acta, Part A 68: 1120–5, https://doi.org/10.1016/j.saa.2007.06.053.Search in Google Scholar

Dossie, R. 1758. The Handmaid to the Arts. London: J. Nourse.Search in Google Scholar

Frost, R. L., and J. T. Kloprogge. 2000. “Raman Spectroscopy of the Acetates of Sodium, Potassium, and Magnesium at Liquid Nitrogen Temperature.” Journal of Molecular Structure 526: 131–41, https://doi.org/10.1016/s0022-2860(00)00460-9.Search in Google Scholar

Fuchs, R., and D. Oltrogge. 1990. “Utilisation d’un Livre de Modeles pour la Reconstitution de la Peinture de Manuscrits.” In Pigments et Colorants de l’Antiquite et du Moyen Age: Teinture, Peinture, Enluminure Études Historiques et Physico-chimiques, edited by B Guineau, and L Holtz, 309–23. Paris: Editions CNRS.10.4000/books.editionscnrs.8189Search in Google Scholar

Gao, J. 1996. “A Theoretical Investigation of the Enol Content of Acetic Acid and the Acetate Ion in Aqueous Solution.” Journal of Molecular Structure: Theochem 370 (2–3): 203–8, https://doi.org/10.1016/s0166-1280(96)04702-1.Search in Google Scholar

Gauthier, J. 1959. “Les Acétates Neutres et Basiques de Cuivre.” Sciences Pures et Appliquées LXVI (2): 67–78.Search in Google Scholar

Gettens, R. J., and G. L. Stout. 1942. Painting Materials: A Short Encyclopedia, 169–70. New York: Dover Publications.Search in Google Scholar

ICDD. 2011. The ICDD Powder Diffraction File (PDF)-2. Newton Square, PA: ICDD Joint Committee on Powder Diffraction Standards.Search in Google Scholar

Kozai, N., H. Mitamura, H. Fukuyama, and F. Esaka. 2005. “Synthesis and Characterization of Copper Hydroxide Acetate with a Layered Crystal.” Journal of Materials Research 20 #11: 2997–3003, https://doi.org/10.1557/jmr.2005.0366.Search in Google Scholar

Kühn, H. 1993. “Verdigris and Copper Resinate.” In Artists’ Pigments: A Handbook of their History and Characteristics, 2, edited by A. Roy, 131ds–58. Washington: National Gallery of Art.Search in Google Scholar

Liu, L., D. Gong, Z. Yao, L. Xu, Z. Zhu, and T. Eckfeld. 2019. “Characterization of a Mahamayuri Vidyarajni Sutra excavated in Lu’an, China.” Heritage Science 7: 77, https://doi.org/10.1186/s40494-019-0320-8.Search in Google Scholar

Mairinger, F., G. Banik, H. Stachelberger, A. Vendl, and J. Ponahlo. 1980. “The Destruction of Paper by Green Copper Pigments, Demonstrated by a Sample of Chinese Wallpaper in Conservation within Historic Buildings.” In Preprints of the Contributions to the Vienna Congress, 7–13 Sept. 1980, 180–5. London: International Institute for Conservation.10.1179/sic.1980.25.Supplement-1.180Search in Google Scholar

Masciocchi, N., E. Corradi, A. Sironi, G. Moretti, G. Minelli, and P. Porta. 1997. “Preparation, Characterization, and ab initio X-Ray Powder Diffraction Study of Cu2 (OH)3 (CH3COO)-H20.” Journal of Solid State Chemistry 131: 252–62, https://doi.org/10.1006/jssc.1997.7372.Search in Google Scholar

Merrifield, M. P. 1849. Medieval and Renaissance Treatises on the Arts of Painting, reprint edition New York: Dover Publications, 1967.Search in Google Scholar

Musumeci, A., and R. L. Frost. 2007. “A Spectroscopic and Thermoanalytical Study of the Mineral Hoganite.” Spectrochimica Acta, Part A 67: 48–57, https://doi.org/10.1016/j.saa.2006.05.037.Search in Google Scholar

Newman, S. P., and W. Jones. 1999. “Comparative Study of Some Layered Hydroxide Salts Containing Exchangeable Interlayer Anions.” Journal of Solid State Chemistry 148: 26–40, https://doi.org/10.1006/jssc.1999.8330.Search in Google Scholar

Ohlidalová, M., D. Seamstress, E. Dytrychová, H. Paulusová, and A. Hostašova. 2015. “Stability Barevné Vrstvy Akvarelu V Podmínkách Umėhlého Stárnutí (Stability of the Aquarelle Paint Layer in the Artificial Ageing Conditions).” Koraze a Ochrana Materiálu 59 (2): 37–49, https://doi.org/10.1515/kom-2015-0013.Search in Google Scholar

Periera, D., D. de Faria, and V. Constantino. 2006. “CuII Hydroxy Salts: Characterization of Layered Compounds by Vibrational Spectroscopy.” Journal of the Brazilian Chemical Society 17 (8): 1651–7.10.1590/S0103-50532006000800024Search in Google Scholar

Prevot, V., C. Forano, and J.P. Besse. 2001. “Hybrid Derivatives of Layered Double Hydroxides.” Applied Clay Science 18: 3–15, https://doi.org/10.1016/s0169-1317(00)00025-9.Search in Google Scholar

Rahn-Koltermann, G., D. Buss, R. Fuchs, and O. Glemser. 1991. “Zur Kenntnis Basischer Kupferacetate. (New Results on Basic Copper Acetate).” Zeitschrift für Naturforschung 46b: 1020–4, https://doi.org/10.1515/znb-1991-0808.Search in Google Scholar

Salvadó, N., S. Butí, M. Cotte, G. Cinque, and T. Pradell, et al.. 2013. “Shades of Green in 15th Century Paintings: Combined Microanalysis of the Materials using Synchrotron Radiation XRD, FTIR and XRF.” Applied Physics A 111: 47–57, https://doi.org/10.1007/s00339-012-7483-4.Search in Google Scholar

San Andres, M., J. M. de la Roja, V. G. Baonza, and N. Sancho. 2010. “Verdigris Pigment: a Mixture of Compounds. Input from Raman Spectroscopy.” Journal of Raman Spectroscopy 41: 1178–86, https://doi.org/10.1002/jrs.2786.Search in Google Scholar

Schweizer, F., and B. Mühlethaler. 1969. “Einige Grüne und Blaue Kupferpigmente (Some Green and Blue Copper Pigments).” Farbe und Lack 74: 1159–73.Search in Google Scholar

Scott, D. A. 2002. Copper and Bronze in Art: Corrosion, Colourants, Conservation. Los Angeles: Getty Conservation Institute.Search in Google Scholar

Scott, D. A., Y. Taniguchi, and E. Koset. 2001. “The Verisimilitude of Verdigris: a Review of the Copper Carboxylates.” Reviews in Conservation 2: 73–91, https://doi.org/10.1179/sic.2001.46.supplement-1.73.Search in Google Scholar

Shahani, C., and F. Hengemihle. 1986. “Influence of Copper and Iron on Paper.” In Historic Textile and Paper Materials, Advances in Chemistry Series 212, edited by H. L. Needles, and S. H. Zeronian, 387–410. Washington, DC: ACS.10.1021/ba-1986-0212.ch022Search in Google Scholar

Stephens, C. H., T. Barrett, P. M. Whitmore, J. A. Wade, J. Mazurek, and M. Schilling. 2008. “Composition and Condition of Naturally Aged Papers.” Journal of the American Institute for Conservation 47 (3): 201–15, https://doi.org/10.1179/019713608804539583.Search in Google Scholar

Švcarcová, S., D. Hradil, J. Hradilová, E. Koči, and P. Bezdička. 2009. “Micro-analytical Evidence of Origin and Degradation of Copper Pigments found in Bohemian Gothic Murals.” Analytical and Bioanalytical Chemistry 395: 2037–50.10.1007/s00216-009-3144-7Search in Google Scholar

Švcarcová, S., M. Klementová, P. Bezdička, W. Lasocha, M. Dušek, and D. Hradil. 2011. “Synthesis and Characterization of Single Crystals of the Layered Copper Hydroxide Acetate Cu2(OH)3(CH3COO)-H2O.” Crystal Research and Technology 46 (10): 1051–7, https://doi.org/10.1002/crat.201100262.Search in Google Scholar

Tomasini, E., C. Landa, G. Siracusano, and M. Maier. 2012. “Atacamite as a Natural Pigment in a South American Colonial Polychrome Sculpture from the Late XVI Century.” Journal of Raman Spectroscopy 44 (4): 637–42, https://doi.org/10.1002/jrs.4234.Search in Google Scholar

Vandenbeele, P., K. Lambert, S. Matthys, W. Schudel, A. Bergmans, and L. Moens. 2005. “In Situ Analysis of Medieval Wall Paintings: a Challenge for Mobile Raman Spectroscopy.” Analytical and Bioanalytical Chemistry 383: 707–12, https://doi.org/10.1007/s00216-005-0045-2.Search in Google Scholar

Van Eikema Hommes, M. 2001. “Verdigris Glazes in Historical Oil Paintings: Recipes and Techniques.” Zeitschrift für Kunsttechnologie Und Konservierung 15 (1): 163–95.Search in Google Scholar

Vargas, J., T. Aria, J. Rodríguez, and Á. Erbez. 2006. “Colour in the Seventeenth-Century Miniatures of Spanish Choir Books.” Restaurator 27: 143–61, https://doi.org/10.1515/rest.2006.143.Search in Google Scholar

Wiggins, M. B., E. Heath, K. S. Booksh, and J. Alcantara-Garcia. 2019. “Multi-analytical Study of Copper-Based Historic Pigments and Their Alteration Products.” Applied Spectroscopy 73 (11): 1255–64.10.1177/0003702819856606Search in Google Scholar

Published Online: 2020-11-24
Published in Print: 2020-12-16

© 2020 Walter de Gruyter GmbH, Berlin/Boston

Articles in the same Issue

  1. Frontmatter
  2. Preface
  3. Editorial
  4. Original Works
  5. Tracing the Alteration of Verdigris Pigment through Combined Raman Spectroscopy and X-ray Diffraction, Part II: Natural Ageing
  6. The Gel, the Colour, and the Complexing Agent: An Investigation of a Rigid Gel Application of Benzotriazole for Verdigris-Damaged Paper
  7. Stabilisation Treatments for Paper with Green Copper Pigment Verdigris
  8. The Colour of Pine Needles and Nightingales. A Traditional Japanese Copper-based Green Pigment
https://doi.org/10.1515/res-2020-0012
Keywords for this article
natural ageing; Raman spectroscopy; verdigris; X-ray diffraction

Articles in the same Issue

  1. Frontmatter
  2. Preface
  3. Editorial
  4. Original Works
  5. Tracing the Alteration of Verdigris Pigment through Combined Raman Spectroscopy and X-ray Diffraction, Part II: Natural Ageing
  6. The Gel, the Colour, and the Complexing Agent: An Investigation of a Rigid Gel Application of Benzotriazole for Verdigris-Damaged Paper
  7. Stabilisation Treatments for Paper with Green Copper Pigment Verdigris
  8. The Colour of Pine Needles and Nightingales. A Traditional Japanese Copper-based Green Pigment
Sign up now to receive a 20% welcome discount
Institutional Access
How does access work?
Have an idea on how to improve our website?
Please write us.
© 2025 De Gruyter Brill
Downloaded on 29.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/res-2020-0012/html
Scroll to top button