Vanessa Antunes

Characterization of glue sizing under calcium carbonate ground layers in Flemish and Luso-Flemish painting – analysis by SEM-EDS, μ-XRD and μ-Raman spectroscopy

This work regards the study of painting techniques in Portuguese workshops of the 15th and early 16th centuries, specifically addressing the methodology used on the preparation of ground layers. The influence of Flemish painting in Portugal is evident in stylistic and iconographic themes of that period. As regards the painting materials, we confirmed that this influence also extended to the ground layer technique. The use of a sizing layer with calcium sulphate or garlic to isolate the support from the calcium carbonate layer was verified by SEM-EDS but not confirmed by μ-XRD or μ-Raman spectroscopy. This work is part of a larger project, “The invisible ground layer and its influence in Portuguese paintings from the 15th and 16th centuries: a question to be settled”.

Characterization of Glue Sizing Layers in Portuguese Wood Paintings from the 15th and 16th Centuries by SEM Secondary Electron Images and μ-FTIR

According to treatises on 15th and 16th century paintings, artists dedicated particular attention to the sizing layer-consisting mainly of animal glue applied onto the wood support before further application of the ground layer. The stability of a painting mainly depends on the presence of a very cohesive sizing layer. However, the study of these layers has not received special attention from researchers. In this article we present a methodology for characterization of the sizing layer both chemically, by IR spectroscopy (Fourier transform infrared spectroscopy), and morphologically, by scanning electron microscopy (SEM). Secondary electron images obtained by SEM allow precise characterization of such layers. Painting reconstructions were used as references in development of the method to study the sizing layer in real painting samples. Presented herein are examples of this study on 15th and 16th century Portuguese paintings, particularly on the Triptych of S. Simão, from the Aveiro Museum, and S. Pedro, belonging to the Mercy of Tavira.

GREGÓRIO LOPES painting workshop: characterization by X-ray based techniques. Analysis by EDXRF, μ-XRD and SEM-EDS

Gregorio Lopes is one of the most famous Portuguese painters of the 15th–16th centuries. This work is a contribution to the study of his painting technique, specifically addressing the methodology used in the preparation of ground layers, which has never been carried out previously with this multianalytical method. For this purpose characterization of the ground layers of a selection of his paintings was carried out by micro-Energy Dispersive X-ray Fluorescence spectroscopy (μ-EDXRF), micro-X-ray Diffraction (μ-XRD), Scanning Electron Microscopy - Energy Dispersive Spectroscopy (SEM-EDS) and complemented by micro-Raman spectroscopy. This work presents the results obtained on two altarpieces (c.1544) produced at the same period by this Portuguese artist. Ground layers are composed mainly of calcium sulfate — anhydrite and gypsum — and other compounds such as dolomite. Reference samples were prepared to obtain diffraction pattern of different percentage of gypsum and anhydrite and compared with the results from historical samples.

Analytical characterization of the palette and painting techniques of Jorge Afonso, the great 16th century Master of Lisbon painting workshop

In this work, a study on a set of paintings from the most significant altarpiece assigned to Master Jorge Afonso (c. 1470-1540) painting workshop is presented. This altarpiece is composed by fourteen paintings made to the church of Convento de Jesus, in Setúbal, Portugal, and was made circa 1517-19/1530, according to art-history. This set of paintings is compared to one of the other most important Portuguese altarpieces from the 16th century: the panels of the Round Church of the Convento de Cristo, in Tomar, made circa 1510-1515. The aim of this study is to characterize the wooden support, pigments, ground layers materials and technique used in Jorge Afonso workshop by means of complementary analyses. A dendrochronological approach was made in order to corroborate (or not) the historical date initially assigned. Infrared photography (IRP) and reflectography (IRR) allowed the study of the underdrawing technique and macro photography (MP) was used to recognize overlapping layers technique. Cross-sections from the paintings were examined by optical microscopy (OM), and analyzed by μ-X-ray diffraction (μ-XRD), Energy Dispersive X-ray Fluorescence spectroscopy (EDXRF), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS), micro-Raman spectroscopy (μ-Raman), micro-Fourier Transform Infrared spectroscopy (μ-FTIR), Pyrolysis Gas Chromatography Mass Spectrometry (py-GC/MS). The characterization of the palette and ground layers and the study of the overlapping of paint layers brought a new insight of the adopted painting techniques by the most important group of painters working in Portugal in the 16th century - the Lisbon workshop, leaded by Master Jorge Afonso.

A multidisciplinary approach to the study of the brightening effects of white chalk ground layers in 15th and 16thcentury paintings

This paper employs various techniques to analyze the mixture of chalk and binder materials used, by Portuguese and Flemish painters in the 15th and 16th centuries, to enhance the reflection of light in paintings. The cases studied show evidence of the search by painters for light effects created when combining specific fillers and binders to obtain absorbent or non-absorbent ground layers in order to reflect superficial or deep light in paintings. These brightening effects are largely provided by microscopic coccoliths and calcispheres – the main constituents of chalk. The composition, size and slightly concave-convex shield-like shape of calcareous nannofossils (micrometrical dimensions) also facilitate application, thereby increasing the speed of handling. These calcareous nannofossils are crucial proof that chalk was used in the ground layers of Portuguese paintings. They have proved to be important in defining the various stages of Portuguese painting workshops, such as the Viseu Workshop (1501–1569), which used powdered chalk in the first phase and powdered limestone in the second phase in the production of a ground layer. A two-layer structure has been verified in some Flemish paintings of the period, but the use of different binders to provide different levels of light absorption and reflection in these artworks had not been previously identified. The results showing this two-layer ground structure are significant in making the connection between Flemish and Portuguese art in the context of a specific painting technique. The use of calcium carbonate ground layers was verified by SEM-EDS and confirmed by μ-XRD, and μ-Raman, while binders were analyzed by μ-FTIR and optical microscopy, using staining tests.

Skill mix in healthcare: An international update for the management debate

Abstract Purpose The interest in health workforce redesign has been growing internationally and over one decade of practice and research resulted in a variety of literature on the impact of the different approaches to staffing on patient and services’ outcomes. The purpose of this review is to produce an update on the knowledge developed on this topic of interest to the international healthcare management community and to policy makers involved in reforming healthcare systems and organizations. Methods A systematic review on healthcare skill-mix literature was conducted in a 4-month period through the Pubmed, BioMed Central, and Medline databases. Fourteen articles published between 1995 and 2011 were selected according to inclusion and exclusion criteria. Findings A total of 14 studies undertaken between 1998 and 2011 were selected for our discussion. The review identified a methodological weakness preventing the results of individual studies from being considered together to produce concrete findings and structured knowledge on the effectiveness of skill-mix experiments. Most studies describing the implementation of skill-mix models were undertaken in the USA and Australia in specific care settings and were mostly focused on doctors–nurses mixes. We found no evidence of a wider impact from a skill mix on health systems nor on the variables that determine its success. Most studies did not explain why a particular approach to skill mix was chosen, nor gave enough information about the context in which decisions were made. There were few appropriate evaluations of outcomes, quality, and costs that enable for effective skill-mix evaluation. Conclusion This review showed that despite the widely acknowledged interest on skill-mix initiatives there is a lack of evidence on skill-mix implications, constraints, outcomes, and quality impact that would allow policy makers to take sustained and evidence-based decisions. There is a need to examine closely the methodological rigor of skill-mix reviews and to be aware of the motivation driving them. Being able to recognize differences between countries and contexts will also allow a better comprehension of the effectiveness of the initiatives and ways to implement them.