Effect of thermal accelerated ageing on the properties of model canvas paintings

The aim of this study is to develop a laboratory technique to simulate a natural ageing of canvas paintings adopting artificial ageing methods in air (thermal oxidation), in the absence of light. Four models of canvas paintings aged up to 315 years are considered. Paintings are constituted of oil film on oil ground layer, oil film on tempera ground layer, tempera film on tempera ground layer or by tempera film on oil ground layer. Surface strength and the colour of the paintings and the degree of polymerization (DP) of linen canvas were evaluated at different steps of ageing. The degradative result was estimated as the DP of linen canvas after prefixed times of microbial attack.     

X-ray radiography and tomography for monitoring the penetration depth of consolidants in Opuka – the building stone of Prague monuments

Stone consolidation is one of the major restoration treatments used for historical monuments preservation. A natural stone is a complicated heterogeneous porous system making the process of consolidation dependent on many variables. In practical restoration aims, for a given stone type, the selection of a suitable consolidant and consolidation conditions therefore remains a complex issue. The impregnation depth is a key factor for the assessment of the treatment efficiency. The combination of state-of-the-art hybrid pixel semiconductor detectors with newly available micro-focus X-ray sources makes possible to apply X-ray radiography, an ideal non-destructive tool, for penetration depth monitoring. In this study, high-resolution X-ray radiography is used for monitoring the penetration depth of organosilicon consolidants in the Opuka stone. The penetration depth has been evaluated in relation to the time of consolidation, stone porosity and consolidation mixtures properties. The exact influence of the X-ray contrast agent on the consolidation depth has been investigated as well. The information obtained provides supplementary knowledge on the suitability of investigated products for the treatment of this type of stone. In our study, the capabilities of X-ray radiography have been demonstrated on X-ray radiography simple projections, high-resolution computed tomography (CT) as well as on the dynamic processes monitoring. The results thus can serve also as an instrumental and methodological example applicable for consolidation monitoring of other stone types.     

Femtosecond laser cleaning of historical paper with sizing

Lasers have served as cleaning tools for historical objects and artworks for about 40 years. In many cases, superior results of laser cleaning were achieved with respect to traditional methods. In this technique, contaminations on the surface of the object are ablated by laser irradiation. In order to apply laser cleaning method to fragile materials such as paper made of cellulose or parchment, heat deposition to the bulk should be minimal, to prevent damage. In this work, it is demonstrated that laser pulses with femtosecond (fs) duration can exhibit non-thermal ablation of contaminants on paper samples. In particular, laser cleaning studies are concentrated on paper samples with sizing. Fs laser cleaning is performed on artificially soiled and aged samples, as well as on historical ones. The laser used in the experiments has pulse duration of 550 fs and 1030 nm center wavelength. The fluence of the laser is varied and the post-cleaning statuses of samples are investigated. The analyses are color changes, fiber integrity, chemical composition changes and mechanical strengths. These results show that fs lasers can be very efficient in cleaning paper samples, yielding minimal discoloration and no damage to fibers distinguishable on microscopic examination. The presence of sizing also provides further protection against possible side effects.     

What do plastics emit? HS-SPME-GC/MS analyses of new standard plastics and plastic objects in museum collections

In recent years, plastics are designated as a source of indoor pollution and particular attention has thus been devoted to the identification of emitting low molecular weight compounds. Headspace-solid phase microextraction-gas chromatography coupled with mass spectrometry (HS-SPME-GC/MS) has been already successfully applied for screening emissions from synthetic materials. This analytical tool being also non-invasive, it has been already successfully applied in the field of cultural heritage science for the identification of volatile organic compounds (VOCs) emitted from various museum objects made of natural materials. In this research, we aimed at assessing the use of HS-SPME-GC/MS as an in situ non-invasive analytical tool for a better knowledge of the volatile organic compounds emitted by plastics in collections. The possibility of characterizing plastics based on their emission signatures was also evaluated. Twelve new standard plastic samples, belonging to seven main polymer families widely present in museum collections as well as three naturally aged museum objects, were investigated. In this paper, we provide a survey of the VOCs emitted, and the use of HS-SPME-GC/MS for identifying volatile marker compounds, degradation products, additives, and monomer residues of the plastic synthesis is evaluated. More than 200 different VOCs were identified from the new standard samples. Two categories of VOCs were distinguished: “non-specific” and “specific” ones. We showed that based on the “specific” VOCs, it was possible to identify the nature of the polymeric matrix itself or at least to unambiguously distinguish a plastic by family. Emissions from the museum objects were then characterised, and main volatile degradation compounds considered as degradation markers of the natural deterioration of polymeric matrices, were identified. This identification procedure could be further exploited for the characterization of VOCs emitted by objects made of multiple synthetic polymers. Complementary to other techniques, this analytical tool is an interesting way to assess the risk for the objects stored in the vicinity of emitting plastics.     

A new class of gels for the conservation of painted surfaces

The application of a new class of organogels as cleaning tools for painted surfaces is described. It combines some of the most attractive features of cleaning liquids and normal gels while diminishing the deleterious characteristics of both. Thus, the ‘latent’ gellant, polyethyleneimine (PEI), reacts with CO₂ at room temperature in solutions of several organic liquids to produce an ammonium carbamate form (PEICO₂). This charged species organizes itself into 3D polymer networks which immobilize the liquids as gels. The properties of the original solution (i.e. a free-flowing liquid) are re-established immediately after addition of a small amount of a weak acid which displaces the CO₂ molecules and makes the PEI chains positively charged. The visual changes are substantiated by rheological analyses. Results from analytical tests to determine the utility of these gels as cleaning tools for painted surfaces of historical and artistic interest, have been obtained from contact angle and FTIR measurements as well as visual comparisons of the surfaces before and after application of the gels. The analyses indicate that the PEICO₂-based organogels were very effective in removing different surface patinas from painted supports. A surface layer of dammar was completely removed from a test canvas with oil paint, an aged painting from the XIX century, and a XV century oil-on-wood panel attributed to Mariotto di Cristoforo. Finally, a surface acrylic polymeric resin (used in a restoration performed during the 1960s) was also successfully removed from Renaissance wall paintings decorating the Santa Maria della Scala Sacristy in Siena, Italy. The isothermally rheoreversible gel approach described in this work represents a new, highly versatile, and very efficient method for removing aged surface patinas from works of art.     

On the Real Limits of Self‐consciousness: Gazing Back at the Subversive Subject with Marco Bellocchio

Abstract

This article looks at Marco Bellocchio’s 2002 film My Mother’s Smile to re‐assess the central feature of Bellocchio’s cinema, i.e. its attempt to delineate a subjective strategy of subversion against a social order perceived as fundamentally repressive. In line with the director’s previous output, the film takes the Catholic Church and the family as its explicit polemical targets, endeavouring to unmask the nefarious ideological pressure they exercise on the ordinary individual in today’s Italian society. However, my reading draws on Lacanian psychoanalytic theory to try and locate the disavowed (unconscious) kernel of Bellocchio’s narrative. Deploying Lacan’s controversial musings on ‘the gaze’, ‘desire’ and ‘femininity’, I suggest that the true stance of rebellion voiced by the film’s protagonist hinges on his recognition that the inconsistency of the ideological predicament he consciously struggles against paradoxically coincides with the traumatic inconsistency at the heart of his own attitude of defiance.     

Re-treatment of whale bones – How to extract degraded fats from weakened bones?

Many whale (baleen whale or toothed whale) skeletons still contain residual lipids even after an initial osteological preparation. This paper examines the different possibilities of re-treatment. Before a conservation intervention, it was necessary to determine the materials of which bones are made up. The samples were analyzed by Raman spectroscopy. Different compounds were identified: a mineral part (apatite), an organic part (collagen) and lipids. Chromatography analysis yielded a detailed composition of the lipids. It was in fact degraded fat with saturated and unsaturated fatty acids. To remove these lipids, several techniques were identified and tested: enzymatic treatments, supercritical CO₂, and green or organic solvents. Esterification catalyzed by lipases could be suitable for a degreasing treatment since the solubility of esters is higher than that of the corresponding fatty acids. The enzymatic treatment acted only on the surface and did not appear to be very efficient. The use of supercritical CO₂ was even less effective. Some green solvents can partially extract lipids but prove difficult to eliminate after treatment. The best results for degreasing were achieved using organic solvents. Different solutions were evaluated at hot or ambient temperature and in simple immersion or with agitation (Soxhlet or pulsed pressure): hexane, heptane, a mixture of hexane/isopropanol, or an azeotropic mixture of methanol/chloroform. Only the mixture of methanol/chloroform succeeded in extracting the overall fat content, but this treatment degraded the organic part of the bones. The other organic solvents extracted mainly colored fat, which generally corresponded to a weight loss of 20 to 50%. The majority of fat was extracted during the first bath. Thus the treatment selected is that of immersion in heptane at ambient temperature. The degreasing of whole bones is less effective because of the film of sticky degraded fat on the bone's surface. A pre-cleaning is necessary to eliminate this film.     

Deacidification of paper relics by plasma technology

With the acidification of paper and paper-containing relics becoming increasingly serious, a convenient, effective and harmless method for deacidification has become an urgent necessity in the protection of paper relics. In this research, a novel method for reducing the acidity of paper by plasma technology is presented, which can be used simply at room temperature and atmospheric pressure. The pH of the paper rises to alkalescence rapidly after treatment and remains stable with no color change, with a slight accompanying increase in the mechanical properties of the paper.     

Cross-border circulation of films and cultural diversity in the EU

This paper explores new data sources on multilateral trade in films among EU countries and with the USA in offline cinema and in online video-on-demand distribution. We observe variations in trade patterns across countries and films and explore how they affect cultural diversity. We find that the EU film market is highly fragmented and cross-border film availability in cinema is low. We explore different aspects of the cultural discount hypothesis by means of a standard Helpman and Krugman (Market structure and foreign trade. Increasing returns, imperfect competition, and the international economy, MIT Press, Cambridge, 1985) trade model with economies of scale and a two-stage Heckman (Econometrica 47(1):153–161, 1979) estimation procedure. Our results show that cultural distance, success in the home market and the size of the film budget influence trade of films between countries. US films have a lower propensity to get into export markets, relative to their success in the home market. Consumer demand for imported films is relatively smaller in large EU economies, except for films imported from the USA that are only marginally affected. We also show that trade patterns in online film distribution are not fundamentally different. As online distribution occurs downstream from theatrical release, online distributors can benefit from cinema market experience to make a better selection of films. This results in a lower impact of domestic market shares on online trade patterns.     

Laser cleaning as a part of the restoration process: removal of aged oil paints from a Renaissance sandstone portal in Dresden,Germany

Laser cleaning was applied to remove aged and soiled oil paints of the 19th century from weathered, brittle sandstone surfaces. In contrast to other tested cleaning methods, the laser technique allows the removal of the oil paint layers with a minimum of material loss in brittle zones. The cleaned test areas have been investigated by optical and scanning electron microscopy as well as by colour measurements. The investigations have shown that the dirt and the oil paint layers can be removed by laser cleaning without affecting the original sandstone surface and that the pores can be opened again. The brown shade after cleaning is not caused by laser interaction with the sandstone surface but by historic impregnation with linseed oil. Immediately after cleaning, a treatment with chemical consolidants is necessary to preserve the brittle sandstone surface. Sustainable consolidation could be problematic in some areas, because the laser cleaning also preserves heavily damaged, crumbling zones of the carvings. For economic reasons, laser cleaning should be applied only in the most endangered zones of carvings and combined with classical methods (organic solvents and scalpel).     

Critic power or star power? The influence of hallmarks of quality of motion pictures: an experimental approach

Most research into the film industry focuses on aggregate level market analysis of a range of devices used by the industry to ensure the success of its films. In contrast, in this paper, we experimentally test how individual cinema-goers are influenced by two variables that have aroused considerable interest in the literature: critical reviews and the role of box office stars. As regards the former, the results of our experiment indicate that negative reviews by film critics are cues that affect cinema-goers’ pre-film assessment of a film yet fail to exert any effect on post-film assessment. As regards the latter, a cast of box office stars is not seen to be an indication of quality per se for our experimental subjects. Nor do box office stars help to mitigate the potential effects of negative reviews.     

On the use of ASTM closed vessel tests in accelerated ageing research

The ASTM D6819-02e3 standard for testing the accelerated ageing of paper, published in 2002, recommends using closed glass vials in order to keep the degradation products in contact with the paper and thus permitting a better simulation of the natural ageing conditions inside closed books. In the present study, the actual conditions and their stability inside closed vessels have been evaluated. The necessity of assuring a very high sealing performance (tightness) of the systems in order to avoid leakage of water vapour is the main drawback of this ageing method. Systematic studies presented in this publication tried to monitor this tightness and have provided data that helped to answer the question of what circumstances could lead to achieving its improvement. Both gravimetric monitoring of water content in vials and “in situ” IR measurements of the aged paper humidity have been applied for this purpose. As a result, better sealing materials (gaskets and caps) than those recommended by the ASTM standard, have been found. Additionally, application of a dynamometric spanner for closing the vials is recommended, as this is a guarantee of reasonably high and recurring tightness of the systems used in tests. Nevertheless, the systematic, linear with time, loss of moisture for all used vials was observed. A 9% loss of the initial moisture content in samples of the aged paper was observed for the tested conditions (14 days at 90 °C). Therefore, it seems that including some kind of gravimetric control for ageing tests performed in closed vessels is of essential importance.Kinetic studies of accelerated ageing in both closed and open systems, as monitored by DP and breaking length measurements, unexpectedly show that no statistically meaningful difference of degradation rates can be observed. On the other hand, the pH and whiteness index values reveal a meaningful difference between the rates of ageing in these systems, thus confirming the basic assumption of the ASTM test concerning the interaction of paper degradation products with the paper itself.     

Water dispersed polymers for textile conservation: a molecular, thermal, structural, mechanical and optical characterisation

With the aim of identifying new water dispersed polymers for textile conservation, the structure and properties of three commercial polyacrylates and one commercial polyvinylacetate were analysed. The characteristics of these materials, not previously used in the conservation and restoration fields, were compared with that shown by Primal AC33 and Mowilith DMC2 and SDM5, widely used as consolidating or adhesive agents of ancient textiles. To achieve a thorough characterisation of each polymer, molecular, thermal, structural and mechanical investigation techniques were applied on film samples, obtained from polymer water dispersions through water casting at room temperature and/or compression moulding. The photo-oxidative resistance of these materials was also assessed by artificial weathering of water cast films and by measuring the Yellowing Index (YI) as a function of the exposure time under xenon-arc lamp. Collected data were used to appropriately compare the performances shown by these polymers when applied on artefacts consisting of natural fibres. In particular it was found that, among the products not previously used in the conservation and restoration fields, a high potential for carrying out treatments on textiles is shown by the samples commercialised with the trade names of Acrilem RP6005 and Acrilem 30WA. These products, in fact, exhibit properties that make them suitable as substitutes for Primal AC33 and Mowilith DMC2 and SDM5, respectively, depending upon conservation needs. It was very interesting to note that Acrilem 30WA, also after aging, shows YI values lower than that shown by Mowilith DMC2 and SDM5.     

A visible and long-wavelength photocured epoxy coating for stone protection

An epoxy coating modified by PDMS hydroxyl terminated is presented in this paper in order to evaluate its potential use as a protective of a stone surface. With a view to its use in restoration sites, visible and long-wavelength photoinitiated cationic polymerization is proposed here. The system investigated is based on a crosslinking mechanism which shows remarkable advantages for stone protection, such as the low toxicity of the products and facility of mixture preparation. Furthermore, the visible light exploitation represents the most important advantage, because it is easy to apply in a restoration site, with or without irradiation instruments. Besides coating characterization through FT-IR, DMTA analyses and contact angle measurement on glass slides, analyses were also carried out on coated plaster samples. These analyses were performed in order to evaluate the effectiveness of the protective, in relationship to hydrophobicity (contact angle measurement, capillary water absorption) and morphology surface changing (SE/SEM observations, colorimetric measurements) before and after polymer application and UV aging test of coated samples. The overall characterization makes it possible to consider it a suitable coating for stone protection.     

The business of film music in mainstream Nollywood: competing without advantage

This article addresses the business of film music in mainstream Nollywood. It does so by focusing on the materiality of the industry as an institution: its social organisation and systems of film music production; markets; networks; and power relations. Specifically, the arguments rely on social organisational theories, and economic concepts such as vertical integration and market competition alongside inferences from interviews with insider-practitioners. Findings reveal that the Nollywood film music industry is characterised by non-institutionalised vertical integration within a perfectly competitive market in which its film music composers are, essentially, competing without advantage.     

A critical analysis of the Nollywood film Osuofia in London

This article analyzes Nigeria’s Nollywood film Osuofia in London [Ogoro, K. (Producer & Director). (2003/2004). Kingsley Ogoro Productions] to understand how the film synthesizes African and Western cultural identities via the prisms of hybridity and postcolonial theory. The paper uses a critical approach within the contexts of three tenets (African, Western, and hybrid) to read the film. The analysis resulted in five themes: African/folk belief systems and Christianity; traditional Igbo attire and English garb; African/folk music and Western music; African and Western food and drinks; and African/traditional medicine and modern medicine. The analysis indicates that unequal power relations and the forces of globalization are inescapable. Even though the protagonist, Osuofia, challenges the Western ideology, he reproduces it as well.     

The ‘diaspora advantage’ of Pauline Chan (1956–): from multicultural filmmaker to cultural broker

ABSTRACT

This is the first academic paper to critically introduce and document the 30-year screen career of Pauline Chan, Australia’s highest profile Chinese film director, television actress and media producer. Sydney-based, Vietnam-born, Hong Kong-educated and US-trained, Chan has directed six films, starred in 14 and produced four television series and films. Despite her prolific career, there has been no sustained research on her profile and repertoire. This paper evaluates the evolution of Chan’s career using the diaspora ‘advantage’ as a new approach. Characterised by mobility rather than culturalism, the term refers to the benefits brought by and skills of diaspora groups that have allowed them to flourish as transnational actors able to leverage resources in both their countries of origin and settlement. It begins by elaborating how Chan’s diaspora advantage has allowed her to challenge welfare multiculturalism and extend aesthetic multiculturalism. It further documents her transition from a multicultural filmmaker to a cultural intermediary by leveraging her diasporic advantage across the film sectors in China and Australia, and opening up new industrial routes outside of the confines of policy. Using interdisciplinary methods to screen biography that include interviews with the filmmaker, film archival research, critical cultural policy studies, and studies in Asian Australian cinema and political economy, this paper argues that the new approach of the diaspora advantage turns the deficit associated with the diaspora into a dividend that has the potential to rethink the imaginary between Asia and Australia.     

Particle-modified consolidants: A study on the effect of particles on sol–gel properties and consolidation effectiveness

In this paper, we have performed a systematic characterization of sol and gel properties for particle-modified silica consolidants filled with titania (TiO₂-PMC), alumina (Al₂O₃-PMC), and silica (SiO₂-PMC) particles. Viscosity of the sol is not increased much by loading with particles, especially for TiO₂-PMC and SiO₂-PMC. Composites show a strong reduction of silicate network shrinkage. Also, the incorporation of oxide particles into the matrix increases the elastic modulus while decreasing the thermal expansion. In agreement with the improvement of bulk gel properties, we observed better performance of PMCs against unfilled silicate upon consolidation of Ohio Massilian sandstone. Notably, the sulfate crystallization test has less effect on PMC-treated than on silica-treated samples.     

Consolidation of carbonate stones: Influence of treatment procedures on the strengthening action of consolidants

This article demonstrates the importance of treatment application procedures on the consolidation effectiveness obtained by comparison of the results obtained using three different consolidants on four carbonate stone types, and proposes a general methodology for assessing the potential effectiveness of consolidants in laboratory conditions. It stresses the relevance of taking into account the treatment methodology, given the influence application protocols can have on the overall behaviour of the consolidated material. Several mechanical properties were assessed to demonstrate this influence on the performance of the consolidant. The results demonstrate that the strengthening action achieved with a specific product can only be defined in a strict relation to the treatment protocol used to produce it. The results also contribute towards the definition of standard testing protocols on stone consolidation. The application of a consolidant by direct contact capillary absorption is a reliable procedure and the results are easier to interpret than others obtained by brushing or by full immersion, thus making this procedure a good candidate for an eventual standard laboratory assessment method of the consolidation action of any specific stone/consolidant combination. This study also showed that the best test method to assess the strengthening action of stone consolidants in soft stones is DRMS (Drilling Resistance Measuring System). Moreover, the collection of longitudinal ultrasound velocity profiles determined in stones specimens treated by contact capillary absorption was shown to be a useful non-destructive method to assess the depth of the strengthening action achieved.     

The Returns to Picasso's Prints and to Traditional Financial Assets, 1977 to 1996

This paper updates prior work by Pesando (1993) regarding art as an investment. Using world-wide auction prices for Picasso prints for the period 1977 to 1996, this paper establishes that (1) a recovery in the art market did occur in the mid-1990s, but (2) the real rate of return on this segment of the art market remains low relative to its risk. Indeed, the real rate of return is beneath that provided by U.S. Treasury Bills.