Geranium lake pigments: The role of the synthesis on the structure and composition

Beltrán, Victoria; Marchetti, Andrea; Meyer, Steven De; Nuyts, Gert; Wael, Karolien De

doi:10.1016/j.dyepig.2021.109260

Cited by 8 publications

(24 citation statements)

References 51 publications

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“…These bands are in the spectral region where some of the main bands of the pink pigments from the family of geranium lakes appear, as it can be seen in the reference spectrum (Figure 4, spectra in pink), meaning that the presence of these pigments is compatible with the results. However, the bands are low, broad and the maximums are slightly shifted from the ones described in literature [41] . Moreover, these signals appear in the same region of other lake pigments employed by the same artist, such as cochineal [34, 42, 43] .…”

Section: Resultsmentioning

confidence: 56%

“…The collected spectra (Figure 5, spectra in black) clearly show the main bands of geranium lakes observed in the reference of the pigment analyzed by the same technique (Figure 5, spectrum in red). In particular, the bands at ≈1550 and ≈1460 (carboxylate group), ≈1605, ≈1351 and ≈1254 (xanthene and ketone groups) of geranium lakes can be identified [41] . It should be remarked that the spectra include also the bands from the other compounds previously detected in the sample: among them lead white and lead carboxylates show bands at ≈1450 and ≈1550 cm −1 that overlap with the peaks of geranium lakes producing slight shifts in the bands.…”

Section: Resultsmentioning

confidence: 76%

“…However,t he bands are low,b road and the maximums are slightly shifted from the ones described in literature. [41] Moreover,t hese signals appear in the same region of other lake pigments employed by the same artist, such as cochineal. [34,42,43] Therefore,t he identification of the type of pigment cannot be unambiguously concluded based in these results.…”

Section: Application Of O-ptir For the Identification Of Micrometric ...mentioning

confidence: 99%

See 2 more Smart Citations

Nanoscale Analysis of Historical Paintings by Means of O‐PTIR Spectroscopy: The Identification of the Organic Particles in L′Arlésienne (Portrait of Madame Ginoux) by Van Gogh

et al. 2021

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Optical‐photothermal infrared (O‐PTIR) spectroscopy is a recently developed technique that provides spectra comparable to traditional transmission FTIR spectroscopy with nanometric spatial resolution. Hence, O‐PTIR is a promising candidate for the analysis of historical paintings, as well as other cultural heritage objects, but its potential has not yet been evaluated. This work presents the first application of O‐PTIR to the analysis of cultural heritage, and in particular to an extremely small fragment from Van Gogh's painting L′Arlésienne (portrait of Madame Ginoux). The striking results obtained, including the detection of geranium lake pigments as well as the complete analysis of the stratigraphy, failed with other state‐of‐the‐art techniques, highlight the potential of this method. The integration of O‐PTIR to the study of cultural heritage opens to the possibility of decreasing the amount of sample extracted, therefore contributing to the preservation of the integrity of artworks while providing a complete characterization of the materials.

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Section: Resultsmentioning

confidence: 56%

Section: Resultsmentioning

confidence: 76%

Section: Application Of O-ptir For the Identification Of Micrometric ...mentioning

confidence: 99%

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Nanoscale Analysis of Historical Paintings by Means of O‐PTIR Spectroscopy: The Identification of the Organic Particles in L′Arlésienne (Portrait of Madame Ginoux) by Van Gogh

et al. 2021

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“…mIRage system used in this study equipped a QCL (MIRcat-QT, DRS Daylight Solutions Inc, USA) with the wavenumber ranged from 800-1800 cm -1 , but the principles and working mode of O-PTIR are different from QCL-IR (LDIR). The photothermal expansion in the sample surface caused by the absorption of infrared radiation will change the intensity of the reflected or scattered light, and the intensity change of the visible light is proportional to the absorption of infrared radiation 35,36 . O-PTIR uses a visible light probe to detect the photothermal event induced by the incident infrared radiation 35,36 .…”

Section: O-ptir Measurementsmentioning

confidence: 99%

“…The photothermal expansion in the sample surface caused by the absorption of infrared radiation will change the intensity of the reflected or scattered light, and the intensity change of the visible light is proportional to the absorption of infrared radiation 35,36 . O-PTIR uses a visible light probe to detect the photothermal event induced by the incident infrared radiation 35,36 . mIRage equipped a 532 nm laser as the probe and a 40× objective (0.78 NA), so the resolution of O-PTIR can be approximately 500 nm.…”

Section: O-ptir Measurementsmentioning

confidence: 99%

Automated analysis of microplastics based on vibrational spectroscopy: Are we measuring the same metrics?

Dong

She

Xiong

et al. 2021

Preprint

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The traditional manual analysis of microplastics has been criticized because it is labor intensive, inaccurate for identifying very small microplastics, and difficult to standardize or compare. There are already three automated analysis strategies for microplastics based on vibrational spectroscopy, laser direct infrared (LDIR)-based particle analysis, Raman-based particle analysis, and focal plane array-Fourier transform infrared (FPA-FTIR) imaging. We compared the performances of these strategies in terms of their quantification, detection limit, size measurement, and material identification accuracy and analysis speed by analyzing the same standard and environmental samples. Unfortunately, the automated analysis strategies are not consistent in terms of the quantification and material identification results. The number of particles smaller than 60 μm recognized by Raman-based particle analysis is far greater than that recognized by LDIR-based particle analysis. Raman-based particle analysis has a submicrometer detection limit but should not be used in the automated analysis of microplastics in environmental samples because of the strong fluorescence interference. LDIR-based particle analysis provides the fastest analysis speed, but we suggest using a reliable detection limit of approximately 60 μm and considering the material identification results and reference database used because the wavenumbers LDIR spectra are in the range of 975-1800 cm -1 . FPA-FTIR imaging provides relatively reliable quantification and material identification for microplastics in environmental samples but might provide an imprecise description of the particle shapes. Optical photothermal infrared (O-PTIR) spectroscopy can detect submicron-sized microplastics (0.5-5 μm) but has not been automated. As a technological advancement, automated analysis of microplastics should be encouraged, but we need to foster the strengths and circumvent the weaknesses of different strategies. The automated analysis of microplastics should be further validated and standardized.

show abstract

Nanoscale Analysis of Historical Paintings by Means of O‐PTIR Spectroscopy: The Identification of the Organic Particles in L′Arlésienne (Portrait of Madame Ginoux) by Van Gogh

et al. 2021

Self Cite

View full text Add to dashboard Cite

Optical-photothermal infrared (O-PTIR) spectroscopyi sarecently developed technique that provides spectra comparable to traditional transmission FTIR spectroscopy with nanometric spatial resolution. Hence,O-PTIR is apromising candidate for the analysis of historical paintings,aswell as other cultural heritage objects,but its potential has not yet been evaluated. This work presents the first application of O-PTIR to the analysis of cultural heritage,a nd in particular to an extremely small fragment from VanG oghsp ainting L'ArlØsienne (portrait of Madame Ginoux). The striking results obtained, including the detection of geranium lake pigments as well as the complete analysis of the stratigraphy,f ailed with other state-of-the-art techniques,h ighlight the potential of this method. The integration of O-PTIR to the study of cultural heritage opens to the possibility of decreasing the amount of sample extracted, therefore contributing to the preservation of the integrity of artworks while providing acomplete characterization of the materials.

show abstract

Geranium lake pigments: The role of the synthesis on the structure and composition

Cited by 8 publications

References 51 publications

Nanoscale Analysis of Historical Paintings by Means of O‐PTIR Spectroscopy: The Identification of the Organic Particles in L′Arlésienne (Portrait of Madame Ginoux) by Van Gogh

Nanoscale Analysis of Historical Paintings by Means of O‐PTIR Spectroscopy: The Identification of the Organic Particles in L′Arlésienne (Portrait of Madame Ginoux) by Van Gogh

Automated analysis of microplastics based on vibrational spectroscopy: Are we measuring the same metrics?

Nanoscale Analysis of Historical Paintings by Means of O‐PTIR Spectroscopy: The Identification of the Organic Particles in L′Arlésienne (Portrait of Madame Ginoux) by Van Gogh

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