Browsing by Author "Valadas, Sara"
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- Annunciation or Adoration? The workshop practice and the hesitations of a Portuguese mannerist painter revealed by infrared reflectographyPublication . Melo, Helena P.; Cruz, António João; Valadas, Sara; Candeias, AntónioThe examination with infrared reflectography of the Annunciation and the Adoration of the Shepherds, two panels from a dismembered altarpiece attributed to the mannerist painter Francisco João (doc. 1558–1595), revealed the first documented example in Portuguese painting of the overlapping of two underdrawing layouts, each with a different subject, in a single panel painting. The paintings were examined under visible radiation and infrared reflectography was used to investigate the underdrawing in terms of the materials, graphic layout and function. Results from a previous study on the ground layers and underdrawing materials of these paintings, obtained with the analysis of micro-samples with microscopic and spectroscopic techniques, were used in the context of this research. Infrared images revealed that the underdrawing of the Annunciation mostly corresponded to the painted image but that two subjects — Annunciation and Adoration — were drawn over the prepared surface of the panel depicting the Adoration. This discovery is the first example of this procedure in Portuguese painting. The comparison with a third panel attributed to the painter, depicting another version of the Annunciation, allowed for the discussion of relevant technical procedures such as the use of cartoons, the responsibility for each main stage of painting creation and the reality of labour conditions in a regional market. The results contributed with material evidence to the scarce information of archival nature about the working methods of Portuguese mannerist painters.
- Charcoal or black stone? Reconstructions as a tool to study the behaviour of dry underdrawing materials within the paint structure of sixteenth century panel paintingsPublication . Melo, H.P.; Valadas, Sara; Cruz, António João; Candeias, AntónioReconstructions were used as a tool to investigate the use of charcoal and black stone as underdrawing materials in sixteenth century panel paintings with white or off-white preparatory layers. Research was based on the examination of a group of sixteenth century panel paintings by the Portuguese Mannerist painter Francisco João (doc. 1558–1595) and his workshop. Analysis of the original underdrawing material in cross-sections, using microscopic and spectroscopic techniques was not always conclusive. Based on materials thought to be employed by Francisco João and on data collected from sixteenth and seventeenth century European technical treatises along with published analytical studies of panel paintings with white or off-white preparatory layers from this period, reconstructions were performed using charcoal (untreated and oiled—as described in contemporary literature) and natural black stone over different preparatory surfaces. Microscopic analyses of cross-sections from reconstructions were made to assist the discussion of the behaviour of the dry underdrawing media within the paint structure. Results revealed that whereas charcoal could be easily removed if drawn directly over gesso, it would remain fixed when drawn over a ground treated with an oil-based intermediate layer, even when the latter was completely dry to the touch. The persistence of a charcoal drawing when applied over oil challenged the widely disseminated assumption that naturally occurring black stone, which makes a permanent mark, had been employed more frequently than charcoal since the latter appeared to be easily disturbed and hence transitory. The very lengthy curing time for a drying oil could be responsible for fixing the friable media. Reconstructions further showed that oiled charcoal is easily prepared and agreeable to use on any type of surface, where it remains without smudging. Finally, research suggests that the painter’s choice of underdrawing material is closely dependent on the nature of the binder of intermediate layers and on the position of the underdrawing layout within the paint structure.
- Images in transformation: The color and its change in a group of Portuguese paintings from the second half of the 16th centuryPublication . Melo, Helena Pinheiro de; Cruz, António João; Sanyova, Jana; Valadas, Sara; Cardoso, Ana Margarida; Candeias, AntónioFour panel paintings depicting episodes related to the birth of Christ and attributed to the Portuguese mannerist painter Francisco João (doc. 1558–1585) were found to exhibit a muted palette that had no correspondence with the traditionally vivid colors used in the sixteenth century to represent joyful biblical events. Complementing previous research on the disruption and loss of the red glazes in these paintings, the investigation focused on the analysis of materials, painting technique and degradation issues that further affected the original paintings, changing the viewer's perception and understanding of these artworks. The investigation combined the visual examination of the painting surface with microscopic and spectroscopic analysis of the binder and pigments. A conventional palette made of lead white, lead-tin yellow, ochres, vermilion, verdigris, smalt, azurite, carbon black and a red lake made of brazilwood and cochineal was identified. The pigments were bound in an oil-based medium. Chemical and physical alterations detected in paints rich in smalt and verdigris were found to be responsible for color changes affecting significant areas of the compositions. The presence of moisture and the reaction between pigment and binder leading, among other products, to soap and oxalate formation, played a central role in the long-term behavior of the paint film. Understanding the main degradation processes involved and their consequences is crucial when interpreting an artists' color palette and designing the best approach to preserve these paintings.
- Italian Influence in a Portuguese Mannerist Painting (Part I): A New Palette with Original Orange and Green PigmentsPublication . Melo, Helena Pinheiro de; Valadas, Sara; Cruz, António João; Cardoso, Ana Margarida; Miguel, Catarina; Manhita, Ana; Helvaci, Yigit Zafer; Dias, Cristina Barrocas; Candeias, AntónioThe palette used by the Portuguese painter Pedro Nunes (1586–1637) in the large panel depicting The Descent from the Cross (460 × 304 cm) painted in 1620 for Évora’s cathedral was investigated with a combination of the visual inspection of the paint surface and the analysis of the paint layers with microscopic, spectroscopic, and chromatographic techniques. Green earth and an orange artificial arsenic sulphide, two pigments identified for the first time in Portuguese paintings of the sixteenth and seventeenth centuries, were found to be abundantly used in large areas of the composition. The results further reveal the choice of a rich palette also containing lead-white, lead-tin yellow, ochre, vermilion, verdigris, smalt, azurite, vegetable carbon black, and a red lake made of brazilwood and cochineal. All the pigments were bound in an oil-based medium. The introduction of two pigments new to the Portuguese conventional palette is a direct consequence of the painter’s training in Rome in the first decade of the seventeenth century.
- Italian Influence in a Portuguese Mannerist Painting (Part II): A Matter of Image or a Matter of Technique?Publication . Melo, Helena Pinheiro de; Cruz, António João; Valadas, Sara; Cardoso, Ana Margarida; Helvaci, Yigit Zafer; Candeias, AntónioThe panel depicting The Descent from the Cross, painted in 1620 by the Portuguese artist Pedro Nunes (1586-1637), shows a clear Italian formal influence. The painter’s colour palette was identified in another paper. The panel is now investigated from a technical perspective, discussing aspects related to the support, preparatory system, and paint layer build-up. The research is based on the visual inspection of the painting’s surface with complementary imaging techniques and on the analysis of the materials from the preparatory layers with microscopic and spectroscopic techniques. The characterisation of the painting technique revealed an ingenious use of colour that is based on the understanding of the optical and handling properties of oil paint. This knowledge is illustrated by the painter’s ability to exploit and combine a range of different oil painting techniques, such as glazing, scumbling, wet-in-wet, or wet-in-dry painting; by his formulation of a wide variety of pigment mixtures; and by his use of diverse and often complex layering systems - some quite unconventional for Portuguese painting practice. The material and technical originality of this painting clearly reflects Nunes’ international Roman experience and his desire to update the Portuguese mainstream practice of his time.
- Paint, Colour, and Style: The Contribution of Minerals to the Palette of the Descent from the Cross, Attributed to the Portuguese Painter Francisco João (act. 1558 1595)Publication . Melo, Helena; Cruz, António João; Sanyova, Jana; Valadas, Sara; Cardoso, AnaThe paint materials and techniques of The Descent from Cross, a panel painting attributed to the Portuguese painter Francisco João (act. 1558–1595), were investigated with a combination of visible, ultraviolet, and infrared imaging and an analysis of paint samples with microscopic, spectroscopic, and chromatographic techniques. The colour palette is composed of lead white, lead–tin yellow, minium, vermilion, ochres of different colours, umber, smalt, azurite, verdigris, charcoal black, and a variety of different-coloured red lakes made of brazilwood and cochineal. An oil-based medium was identified. The characterisation of the pigment mixtures, paint build-up, and particular paint handling techniques enabled us to determine their role in the style and formal appearance of this painting and to discuss Portuguese painting practices in the larger context of 16th-century European painting. Mineral and elemental associations or impurities in the blue pigments, as well as degradation issues affecting minium, and smalt paints were reported. In particular, the deterioration of the glass matrix in some of the smalt particles mixed in lead white paint raises special concern.
- Regraxar or glazing: aspects of this technique in a group of Portuguese paintings attributed to Francisco João (active 1563 95)Publication . Melo, Helena Pinheiro de; Cruz, António João; Sanyova, Jana; Candeias, António; Mirão, José; Valadas, Sara
- The Drawing Hand of a Portuguese Mannerist PainterPublication . Melo, Helena Pinheiro de; Cruz, António João; Valadas, Sara; Candeias, Antóniohe materials and graphical layout of the underdrawing of two sets of paintings attributed, on stylistic grounds, to the workshop of the Portuguese painter Francisco João (doc. 1558-1595) were investigated using infrared reflectography. Two types of underdrawing were found. Comparison between each group of paintings enabled to identify a characteristic drawing style that can be of assistance in future studies on the work of Francisco João. Material evidence related to the painting technique and the underdrawing layout suggests that the painter was responsible for both the underdrawing and the painting stage. This relevant information sheds new light into the working conditions of regional mannerist Portuguese workshops and contributes with material data to the scarce information on these issues found in historic documentary sources.
- The Matter from Which an Orange Colour Is Made: On the Arsenic Pigment Used in a Portuguese Mannerist PaintingPublication . Cruz, António João; Melo, Helena P.; Valadas, Sara; Miguel, Catarina; Candeias, AntónioThe painting The Descent from the Cross, painted in 1620 by Pedro Nunes (1586–1637), presents two large figures with orange-coloured fabrics with conservation problems. Through the analysis of two samples with several analytical techniques, especially scanning electron microscopy combined with X-ray spectroscopy and Raman microscopy, it was possible to conclude that the orange colour is due to a complex artificial pigment made of amorphous arsenic sulphide. It essentially consists of spherical particles obtained by sublimation and condensation, possibly from orpiment, which ended up being joined with irregularly shaped particles resulting from crushing of the residual fraction obtained by solidification and fusion. This is a rare documented case of the extensive use of artificial arsenic sulphides in European easel painting, especially outside Italy. The conservation problems can be explained by the great sensitivity of the arsenic sulphides to photodegradation and the formation of powdery compounds.
- The use of glass particles and its consequences in late 16th century oil painting: A Portuguese case based on the analytical results and the technical treatisesPublication . Melo, Helena P.; Cruz, António João; Valadas, Sara; Cardoso, Ana Margarida; Candeias, AntónioColourless glass particles were identified for the first time in Portuguese paintings in two altarpieces attributed to the painter Francisco João, active between 1558 and 1595. They were found in red glazes with conservation problems. The glass was analysed by SEM-EDX and the binder by μ-FTIR. Portuguese 17th century painting treatises, which record earlier practices, were examined providing additional information. The glass particles had a vegetable silica-soda-lime composition, different in the two altarpieces, and a medium to very high alumina content. Although the provenance of the glass could not be determined, the use of local glass is suggested, as archaeological glass of the same period and similar composition has been found in southern Europe, notably Portugal. Furthermore, the glass from one of the altarpieces closely matches the composition of glass found in a painting by the Spaniard Luis de Morales. As a result, it is possible that the painter deliberately added a local glass to his red lakes, as advised in the two Portuguese painting treatises of this period. The exclusive presence of glass in the uppermost medium-rich glazes suggests that it was mainly used for its transparency and assumed siccative role. Although the siccative properties of glass have not been proved, by lowering the oil concentration in the paint, the addition of glass might have indirectly assisted the drying of the glazes. The glass particles were subject to a severe leaching of the alkali, a degradation that might explain the disruption of the glaze layers in these paintings.