Abstract
Fires can have a negative impact on the environment, human health, property and ultimately also on various objects of cultural heritage (CH). This paper deals with an investigation into the ...degradation of selected proteinaceous paint layers that were exposed to fire-related effects (i.e., fire effluents and/or high temperatures) in a modified cone-calorimeter system. Paint layers of egg yolk adhesive (E) and lead white tempera (E + LW) were exposed to fire-related impacts on top of a CH stack and in a specially designed CH test chamber. On the CH stack, the proteinaceous paint layers were exposed to fire effluents and high temperatures, while in the CH test chamber, the samples were exposed mainly to fire effluents. The molecular changes to the exposed paint layers were analysed by invasive and non-invasive spectroscopic analyses (i.e., FTIR and Raman spectroscopy) and complimented with pyrolysis-GC–MS, while the colour changes were evaluated using colourimetry. It was concluded that the proteinaceous binder degrades into aromatic amino acids and/or fatty acids after exposure to the overall impacts of the fire. Aromatic amino acids were detected by means of the FTIR and py-GC–MS analyses. In the case of the lead white tempera exposure, partial dissociation of the lead white pigment was confirmed by the detection of alteration products, such as lead oxide and lead carbonate. Moreover, the investigation of the E + LW samples exposed for longer times revealed the presence of lead carboxylates. On the other hand, no significant molecular changes were observed with the CH samples exposed to fire effluents in the CH test chamber. The research offered us an insight into the fire-induced effects on selected paints for the first time.
Raman spectral references for various formulations of iron gall inks, logwood inks and mixtures of both types were acquired during this study. The samples, either liquid or dry inks and applied on ...paper, were analysed using a portable Raman spectrometer, both with 852 and 785 nm excitation lines, and a confocal dispersive Raman microscope with two different excitations, namely 785 and 532 nm. It was found that longer wavelengths are more suitable for the analysis of iron gall inks and that the spectral response of logwood inks is relatively more dependent on the excitation line. For the mixtures, it is suggested analyses be performed with both longer and shorter wavelengths, since with a 785 nm line mainly the characteristic features of the metal-polyphenol complex in iron gall inks are detected, while the spectra collected with a 532 nm excitation contain information on the presence of logwood inks. The study was complemented by non-invasive reflectance infrared spectroscopy, which enabled the detection of tannic acid in iron gall inks and in the mixtures, and by micro-Fourier transform infrared (FTIR) spectroscopy to complement the reference set. The study aims to contribute to the development of non-invasive protocols for identification of inks in historic and artistic works on paper, such as manuscripts and drawings.
Graphical Abstract
This research paper presents a novel methodology for determining the burn temperature of archaeological bones using electron paramagnetic resonance (EPR) supported by Fourier Transform Infrared ...(FTIR) spectroscopy. A selection of bone samples, burned at different temperatures, were examined with EPR. The EPR spectra displayed dependency on burn temperature, showing characteristic narrow spectra of carbon radicals, Mn
2
+
signals and signals from different carbonate ions. This methodology was applied to selected archaeological samples of burnt bones, successfully determining the burn temperature these bones were exposed to in the past. The extracted burn temperatures showed good agreement with those determined from a complementary reflectance FTIR study.
Literature research revealed that scientific work on the characteristics of historical decorative laminates (DLs), like typology, and particularly the material-technical aspects related to the ...composition and build-up is scarce in the field of conservation-restoration of modern materials. This paper aims to take the first step towards filling in this knowledge gap by demonstrating that an in-depth literature research and complementary chemical-physical analytical techniques are useful in characterising and contextualising historic decorative laminates. This research focused on gaining additional information within chemical analyses on material-technical insights. This could serve as a basis for a more comprehensive historical context. Several historical samples from different sample-catalogues and museum objects, spanning a period from 1953 to 1993, were collected and their respective cross-sections were characterised with infrared (mapping), FT-Raman, and dispersive micro-Raman spectroscopy. The different layers, such as the protective, decorative, and core layers were investigated, and materials such as melamine formaldehyde, urea formaldehyde, cellulose, lignin, titanium dioxide (rutile), zinc sulphide, synthetic organic pigments PR112 (monoazo pigment, Naphthol AS), and PG8 (azo metal complex, Pigment Green B) were detected.
Graphical Abstract
Laminar flow cabinets (LFCs) ensure a safe working space within which product manipulation can be carried out safely excluding contaminations of the product with the environmental microorganisms. ...However, for environmental monitoring applications mobile laboratories are required and these prefer the lighter gloveboxes (GB; restricted arm movement) or still air boxes (SAB; free arm movement) over the heavier, more expensive LFCs, which need to be regularly maintained. Nevertheless, the efficiency of simple GBs/SABs (no HEPA filter), in providing semi-sterile working conditions has yet to be clearly defined. Consequently, our aim was to assess the suitability of GBs/SABs for semi-sterile applications by using passive and active bioaerosol sample collection procedures within the interior spaces of these boxes. Prior to sample collection the boxes were pre-treated with different spraying preparations (70% ethanol, 2% detergent or sterile water). For a greater restriction of bioaerosol entry, SABs were constructed with covered arm ports and these were classified as partially covered (SABPC) and completely covered SABs (SABCC). Results showed that ethanol sprayed GB and SABCC exhibited microbial aerosol colony counts of zero after one hour of passive sample collection, and active sample collection revealed counts ranging between 1.9 (for GB) - 2.3 Log10CFU/m3 (for SABCC). However, ethanol sprayed SAB and SABPC were ineffective having colony counts of 6.9 and 6.5 Log10CFU/m3, respectively. Other spraying regimes resulted in even higher colony counts (up to 7.3 Log10CFU/m3). Therefore, the ethanol sprayed GB and SABCC could effectively be used for semi-sterile applications, with the SABCC allowing for an unrestricted arm movement within it.
•GB and SABCC sprayed with ethanol exhibited microbial colony counts of zero after 1 h of passive sampling.•SABCC allows for the full freedom of hand movement.•SABPC and SABUN showed unsatisfactory results in any of the spraying treatments.
•Fungal biodeterioration of photographic materials is reviewed.•Fungal isolates from biodeteriorated photographic materials are analysed•Origins of fungal contamination, prevention and control ...measures, and binder and support material deterioration is discussed.
Despite controlled relative humidity in archives and private collections, fungi are a widespread cause of biodeterioration of cinematographic films and historic photographs, which represent a significant cultural and historic loss to society. Photographic emulsions and coatings are organic and hygroscopic in nature and represent a good and easily accessible source of nutrients. Because archives hold whole stacks of these materials, they subsequently contain more fungi in comparison to other enclosed spaces. This in turn generates a need for a systematic microbiological evaluation of fungi isolated from photographic documents in order to pinpoint the potentially biodeteriorative fungal species and increase awareness and control readiness when these species are encountered. With this aim, we have decided to collect data regarding fungal isolates and their biological potency from the following originating materials: gelatin cellulose triacetate or cellulose nitrate films, albumen or gelatin paper photographs, cellulose nitrate negative films, gelatin glass plate negatives and positive paper prints. In addition, the most efficient biotic degraders of gelatin binder are presented and the degradation of cellulose based supports as well as the occurring microbial interactions and the impact of inhibitory silver salts are reviewed. Lastly, based on the origins of fungal contamination and the occurrence of fungi related to allergenic and toxicogenic diseases, prevention and control measures are suggested.
•Bronze samples and archeological sample were treated with corrosion inhibitor TMI.•Changes due to acetic and formaldehide vapours were documented weekly.•Corrosion development was evaluated by image ...analysis.•TMI inhibited both bare and oxidized bronze sample.•TMI protected the surface of excavated archeological sample sufficiently well.
A corrosion inhibitor, tolyl methyl imidazole (TMI), was tested in practice and verified in a polluted indoor atmosphere. Special attention was given to its behavior in indoor storage conditions, where volatile organic pollutants may cause damage to metal artefacts. Prepared samples of bronze and oxidized bronze were exposed to acetic acid vapors. Raman analysis showed copper acetate and copper nitrate formation. Suppression of corrosion development following the application of tolyl methyl imidazole (TMI) was observed. A simple method based on image analysis for corrosion evaluation was specifically developed. The TMI inhibition action was tested on a Roman archeological object and evaluated after exposure to indoor pollutants.
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In this study, a painted beehive panel from the collection of the Slovene Ethnographic Museum was examined with respect to its material composition with the aim to reveal the painting technique. Due ...to the state of degradation due to outdoor weathering (UV irradiation, rainfall, extreme temperature and humidity fluctuations), as well as past conservation interventions, the object represented a complex analytical challenge. We aimed for non-invasive techniques (FTIR in reflection mode, Raman spectroscopy and hyperspectral imaging in the range of 400–2500 nm); however, in order to explore paint layers, cross-sections were also analysed using Raman spectroscopy. FTIR spectroscopy in transmission mode and gas chromatography coupled to mass spectrometry were also used on sample fragments. Various original materials were identified such as pigments and binders. The surface coating applied during conservation interventions was also characterised. Additionally, organic compounds were found (oxalate, carboxylate), representing transformation products. The potential use of Prussian blue as a background paint layer is discussed.
In this work, we showed the potential of photoreduced surface‐enhanced Raman spectroscopy or surface‐enhanced Raman scattering (SERS) substrate for the detection of organic colourants (in mixtures) ...in lipid and proteinaceous paint layers. Different organic colourants such as madder lake pigment, cochineal lake pigment and lac dye were included in the study. SERS procedure with different approaches was tested, namely, direct application, soaking (incubation) of the sample in the substrate and hydrolysis with the hydrofluoric (HF) acid vapours. For the analysis of colourants bound in linseed oil, a pretreatment step was required (soaking/incubating or hydrolysing with HF). Moreover, exposing a cross‐section of a sample taken from a polychrome work of art to the vapours of HF enabled SERS detection of the cochineal lake pigment in the paint layer of this cross‐section. Therefore, the SERS substrate could be used also for the study of stratigraphy of real cultural heritage samples. As the analyses by means of SERS are (minimally) invasive, the potential of noninvasive reflection FTIR‐spectroscopy analyses for the identification of organic colourants was tested as well. Reflection infrared spectra of organic colourants are presented and discussed. Furthermore, within this study, it was shown that madder lake pigment could be identified in paint layers based on the characteristic bands of the hydrated alumina.
The potential of photoreduced SERS substrate for the detection of the organic colourants (in mixtures) in lipid and proteinaceous paint layers is presented. Three different organic colourants and the cross‐section of the sample from a polychrome work of art were included in the study. As the analyses by means of SERS are (minimally) invasive, the potential of noninvasive reflection FTIR analyses for the identification of organic colourants was tested as well.
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