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Do Espírito do Lugar - Música, Estética, Silêncio, Espaço, Luz

 | 
Antónia Fialho Conde
, 
António Camões Gouveia

3. Da conservação da memória

How did they do it? The mural painting workshop at the Convent of São Bento de Cástris

Milene Gil, Joana Costa, Luís Dias, António Candeias and José Mirão

Abstract

O presente trabalho descreve a caracterização realizada nas pinturas murais seiscentistas localizadas no teto abobadado do refeitório do Convento de São Bento de Castris, a 5 km da cidade de Évora. O objetivo foi identificar as técnicas de pintura e os materiais utilizados pelos pedreiros e pintores nas 20 cenas de uma campanha decorativa. Fotografias em luz visível e rasante foram efectuadas in situ. Microscopia ótica no visível e no ultravioleta, microscopia eletrônica, complementada com espectrometria de energia dispersiva de raios-X (M E V-E D X), foram levados a cabo em micro amostras recolhidas de camadas cromáticas. Os resultados mostram que todas as pinturas seguem o mesmo modus operandi: dois tipos de argamassas de cal como suporte pictórico; uma camada de cal empregue como pigmento, mas aparentemente também, como fundo; desenhos preparatórios feitos à mão livre com ocre vermelho e técnica de pintura mista (fresco e pintura a cal). Um dado curioso a assinalar são as marcas das unhas como aparente método de controlo da consistência ideal da superfície para começar a pintar a fresco.

The present paper describes the characterization carried out on the 17th century murals paintings located in the vault ceiling of the refectory of Convent of São Bento de Cástris, near the town of Évora. The goal was to ascertain the painting techniques and the materials used by the masons and painters in the 20 scenes of an decorative campaign. The analytical setup comprised in situ visible and racking light photography. Optical microscopy in visible and UV fluorescence, electronic microscopy, coupled with energy dispersive X-ray (SEM-EDS), were carried out in collected micro samples. Results shows that all the paintings follow the same modus operandi: two types of lime mortars as pictorial support, a layer of whitewash used as a pigment but apparently also as a white ground and under drawings made free hand with red ochre and a mixed pictorial technique ( fresco and lime painting). A curious finding was the nails marks around the figures as a method to control the surface smoothness to start the fresco painting.

Full text

The authors wish to thank DGPC and DRCAlentejo for allowing this study; the Fundação para a Ciência e Tecnologia for financial support (Post-doc grant SFRH/BPD/63552/2009) through program QREN-POPH-typology 4.1., co-participated by the Social European Fund (FSE) and MCTES National Fund and Project PRIM’ART PTDC/CPC-EAT/4769/2012, funded by FCT/MEC and co-funded by Fundo Europeu de Desenvolvimento Regional (FEDER) through the program COMPETE. They acknowledge also the professional photographer Manuel Ribeiro (http://www.mrfotosonline.com).

Introduction

  • 1 Serrão V., A Pintura Pro-Barroca em Portugal, 1612-1657, Vol. I, Dissertação de Doutoramento em His (...)
  • 2 Monteiro P., A pintura Mural na região do mármore (1640-1750), Estremoz, Borba, Vila Viçosa e Aland (...)
  • 3 Serrão, V. O fresco maneirista do paço de Vila Viçosa: Parnaso do Duques de Bragança (1540-1540), V (...)
  • 4 There are still few scientific studies on Portuguese mural paintings. The most recent concerning mu (...)

1Mural paintings were one of the most recurrent arts in the Southern Portugal (Alentejo region) and it has reached its maximum splendor in the sixteenth and seventeenth centuries1, 2, 3. However, little is still known about the operant modus of its performers4. Knowledge of the raw materials and paintings techniques used to execute wall paintings is essential in the fields of history of art and for proper conservation projects. The mural paintings in the vault of the Refectory of the former Cistercian convent of São Bento de Castris dated 1605 are not exception. The decorative cycle is composed of 20 painted medallions with Ø1m and it depicts three iconographic themes: the four seasons, the twelve months of the year and the four elements (Fig.1).

  • 5 Serrão V., Os focos de pintura mural da Santa Casa da Misericórdia de Montemor-o-Novo (séculos XVII (...)

2The most curious are the twelve months which pictures the everyday life of 17th century social classes of local communities (Fig.1). All the paintings in the vault are presumed to be a labor of José de Escovar workshop, due to stylistic and pictorial similitude’s with another mural painting cycle, undoubtedly assigned to this painter, in the town of Montemor-o-Novo (Casa do Despacho da Santa Casa da Misericórdia)5.

3The paintings have never been intervened, thus keeping its originality intact. It is a unique opportunity to study the materials (composition and origin), the painter palette (and its alteration) and paintings techniques. The technical and analytical study were perform within the framework of projet PRIM’ART_Portugal Rediscovering Mural Art: historic and scientific study of Évora Archiespiscopal (1516-1615). The obtain data will enable comparison with other paintings attributed to the same painter and the paintings diagnostic prior a conservation-restoration treatment.

Fig 1 - Overall view of the decorative cycle:1-Estio;2- June; 3- Autumn; 4- Winter; 5- May; 6- Summer; 7- September; 8- April; 9- October?; 10- August; 11- November; 12- July; 13- April; 14- December; 15- Wind; 16-February; 17-Water;18- Fire; 19- January; 20- Earth.

Fig 1 - Overall view of the decorative cycle:1-Estio;2- June; 3- Autumn; 4- Winter; 5- May; 6- Summer; 7- September; 8- April; 9- October?; 10- August; 11- November; 12- July; 13- April; 14- December; 15- Wind; 16-February; 17-Water;18- Fire; 19- January; 20- Earth.

(photos Manuel Ribeiro 2013)

Experiment

4The paintings visual inspection and photographic documentation were the first step of in situ technical examination. Conventional visible light photography (Vis) was perform on the twenty medallions in order to gather data of the intrinsic characteristics of the whole for comparison, such as drawings transposition techniques, pentimenti, the colors of the paint layers and mortars, surface appearance and state of conservation. During this first survey, scene 5,6,7,9,10,13,16,18,19 and 20 were chosen for a closer look with racking light photography (RAK). Vis e RAK photos of each scene were acquired in six mosaics with a Nikon D3200 24Mpx with an objective Nikkor 18-55mm f: 3.5-5.6 G II ED and a flash Nikon SB24. The photos assembling and edition were made in Adobe Photoshop CS5.5. Raking light photography was made using the illuminant at an angle of 5-20º from the surface. The photos were acquired with raw image output in combination with a grey color profile Qpcard101 in order to get a more accurate and comparable color registration. The photographic documentation was carried out by a professional photographer of Projet PRIM’ART.

5For further technical and material analysis, micro samples of paint layers were taken out in scenes 5,7,9,13 and 16 with a scalpel at the paint lacunae and cracks. They were analyzed in optical microscopy (OM) and electronic microscopy (SEM-EDS) as cross sections to gather data about the number, thickness and paint layers stratigraphic succession; pigments physical and optical properties; mortars and paint layers and elemental composition. Two microfragments of mortars were also collected in order to determine their mineralogical phase composition with X-ray diffraction (XRD).

6The samples cross sections for pigments and binders identification were mounted in an epoxy resin (Epofix Fix, Struers A/S, Ballerup, Danmark) and polished with 1200 sandpapers SIC-Paper Grif in a rotation disc Drehzal Regler (Jean Wirtz, Dusseldorf, Germany). The optical microscopy observations were acquired with an optic Leica DM2500M microscope with reflected light in dark field illumination and UV fluorescence modes. The corresponding photographic documentation was taken with a Leica DFC290HD digital camera (Leica Microsystems, Wetzlar, Germany).

7For SEM-EDS analysis was used a scanning electron microscope HITACHI S3700N coupled with an X-Flash5010 X-ray energy dispersive spectrometer (Bruker AXS, Berlin, Germany). The SEM images were obtained on backscattering (BSE) mode. The cross sections were not coated and they were analysed under variable pressure.

8X-ray powder diffraction (XRD) analysis was carried out on the collected plasters that were ground in an agate mortar. XRD was made with a commercial Brucker AXS-D8 Advance diffractometer with CuKα radiation. The samples were mounted as powder on a zero background silica sample holders. A step of 0.02º/s was used for collecting 2-70º 2θ diffractograms. The software EVA code (Brucker Company) was used for index the diffraction pattern and phase analysis.

Results and discussion

Pictorial support and painting technique

9Three layers of mortars can be distinguish from the paint lacunae of scene 6 severely damaged by salts: 1) a brownish-grey inner layer composed of lime and coarse aggregates applied to even out the vault masonry; 2) an intermediate brownish-grey layer and 3) a whiter finishing layer made of lime and finer-grain aggregates that receives the painting. The qualitative mineralogical composition of two samples from layer 2 and and 3 are given in table I.

Table I - Mineralogical composition by X-ray diffraction

Table I - Mineralogical composition by X-ray diffraction

10XRD data underlines the regional granitoid character of the aggregates with major minerals like quartz, feldspars and micas. The binder in of both is calcite thought a component of magnesium carbonates (magnesite) was also identified. Both minerals can be found in the geological environment around Évora. It is worth noting that a few meters from the Convento there were the São Bento Quarries, which held some olivinic gabbros outcrops. The presence of mineral olivine, with the formula (Mg+2,Fe+2)2SiO4, is also suggested by XRD results.

11The surface of the mortars are quite smooth. With racking light marks of trowels used to laid down and flattening it are hardly seen. In almost all the paintings, a layer of whitewash was spread on top of the whiter finishing layer. This layer serves as a pigment but apparently also as a white or whitish blue ground. Traces of giornate, a typical day work of fresco technique, are not visible, probably due to paintings small size, but another evidence prompts that this technique has been used. By racking light, several marks of nails are identified around the figures, suggesting that the painter was controlling the right moment to start to paint (Fig.2). The transparence of some of the paint layers seems to indicate a buon fresco technique. Thicker and opaque brushstrokes are also seen by RAK photos, implying that the pigments were previously mixed with lime. In this case, the paint could have been laid down in a fresh mortar (lime fresco), in a later stage of the carbonation process or already at secco (lime painting). Most paintings have highlights made with slaked lime (Fig.2.).

Fig 2 - Details of the painting technique in racking light

Fig 2 - Details of the painting technique in racking light

(Photo Manuel Ribeiro 2013)

Under drawing

12Under drawings made with red ochre have traced all the compositions. The under drawings are under the paint layers and are hardly seen in the paintings in good state of conservation. In the more damaged ones, where the paint layers have already fallen of, we can easily see the sketched lines. They outline the figures anatomy and drapery without shading it (Fig.3). In some, it can be seen that the painter has made adjustments until he has reached the final form. The stylistic differences among the paintings suggest two hands working at the vault. The drawings of the four elements and seasons are more refined that the compositions of the months. In both cases, the outlines were re-drawn with brown ochre in the final stage of the painting. No other form of under drawing was

13found by visible and racking light.

Fig 3 - Details of the under drawings made free hand by brush with red ochre’s

Fig 3 - Details of the under drawings made free hand by brush with red ochre’s

(photo Manuel Ribeiro 2013)

Paint layers

14In almost all the scenes, the absence of details accuracy suggest a fast paint execution without stylistic concerns resulting in a rather naïf but very efficient painting composition to been seen from the ground floor (Fig.1,2 and 3). This is particularly true for the figures of the months.

  • 6 Piovesan, R., Mazzoli C., Maritan L., and Cornale,P, « Fresco and Lime-Paint: an experimental study (...)
  • 7 Cornell, R.M., Schwertmann U., The Iron oxides: structure, properties, reactions, occurences and us (...)

15The colors were laid down in one to three layers being the superimposition generally connected to the presence of red under drawings, shadings or details in background elements (such as trees for example). In buon fresco, the pigments are only mixed with water and laid down in the fresh plaster. As the cross section of figure 4a shows, the resulting paint layer is usually thin and often can been noticed a slight diffusion of the pigments particles into the underneath plaster. When lime is added to the pigments, the thickness of the paint layer increase (Fig 4b and c). As cited above, pigments mixed with lime milk can be applied in a fresh or in a dry (or almost dry) surface. According to a recent study6, it is possible to distinguish between these two pictorial techniques in a cross section by the absence or presence of a thin carbonation layer at the interface of the plaster with the paint layer. The presence of a carbonation layer clearly indicates that the pigments were spread at mezzofresco or already at secco. In the paint layers that were studied by electron microscopy, in backscattering mode, these two situations were detected, strongly suggesting that a mixed pictorial technique was used by the painter (Fig.4). Apart from lime, no other binder was identified by the analytical setup. In what concern the pigments, and as expected, mainly earth pigments were used ranging from yellow to red and its intermediate orange and brownish hues. These pigments also known by ochre’s are among the natural colorant more suitable for fresco and lime painting murals because of their coloring capacity, stability in an alkaline environment and under varied weathering conditions7 Their color is given by the presence and nature of iron oxi-hydroxides and oxide chromophore, especially hematite and goetite (Fe2O3 and Fe(OH)2) (Fig.4 a and c).

  • 8 Renzoni M., «Sull’ uso della tempera nella techniche ad afresco», KERMES, 30, 1997, 3-10.

16The blue pigment smalt, a potassium glass with cobalt oxide as chromophore, was found in the bluish and bluish grey paint layers of the sky and drapery. Being a crushed glass, this pigment is identified in optical and electronic microscopy by the angular and fractured shape edges particles and by the potassion (K), cobalt(Co), silicium (Si), arsenic (As) and bismuth (Bi) content that are typical elements of smalt composition. Smalt pigment in all the micro samples analyzed was used mixed with lime (Fig.4b). According to old recommendations, mixing only smalt with water was insufficient for preparing and laying down the pigment on the surface because of its sanding and coarse particles8. It can be assumed that smalt pigment was not suitable for a buon fresco technique but only for lime fresco or for secco painting (such as lime painting). The painter ( or painters) that have worked in the vault of the refectory were aware of this fact. Carbon black, made from wood and bones, was found in the black paint layers. Finally, malachite (Cu.CO3.Cu(OH)2) a basic copper carbonate was identified in the greens colors analyzed,. This pigment has flaked of in almost all the scenes (Fig.2).

Fig 4 - OM and SEM images of paint layers. The rows indicate the presence of the carbonation line at the interface of the mortars with the paint layers

Fig 4 - OM and SEM images of paint layers. The rows indicate the presence of the carbonation line at the interface of the mortars with the paint layers

Final notes

17The research carried out on the painted surface provided an unique opportunity for finding out more about the materials and techniques used at the vault of the refectory of the former Cistercian Convent of São Bento de Cástris. The paintings are dated 1605 and are most likely a work of José de Escobar, considered by art historians one of most laborious and active painters working in Évora Archiepiscopate between 1585 and 1622. It is known that José Escovar worked with apprentices and co-workers which could explain stylistic differences between the paintings. All the paintings studied in Vis and RAK light have follow the same modus operant: at least two layers of mortar being the superficial one more white, flat and smooth; a layer of whitewash used as pigment and apparently as a white ground too; under drawing made free hand with red ochre; marks of nails that seems to control the right moment to paint and finally the painting made with pigments mixed with water and also with lime milk applied at fresco but also in a partial or already dry mortar (lime painting). Analytical data also suggest that local raw materials could have been used for mortars (lime and aggregates). The pigment palette composed mainly of earth pigments is also in agreement with what was recommended for fresco mural paintings.

Notes

1 Serrão V., A Pintura Pro-Barroca em Portugal, 1612-1657, Vol. I, Dissertação de Doutoramento em História de Arte apresentada à Faculdade de Letras da Universidade de Lisboa, Coimbra1992.

2 Monteiro P., A pintura Mural na região do mármore (1640-1750), Estremoz, Borba, Vila Viçosa e Alandroal. Dissertação de Mestrado apresentada à Faculdade de Letras da Universidade de Lisboa, 2007.

3 Serrão, V. O fresco maneirista do paço de Vila Viçosa: Parnaso do Duques de Bragança (1540-1540), Vila Viçosa, Fundação da casa de Bragança, 2008.

4 There are still few scientific studies on Portuguese mural paintings. The most recent concerning mural paitings from Southern Alentejo are: Gil M. et al, Are they fresco paintings? Technical and material study of Casas Pintadas of Vasco da Gama House (Southern Portugal). X-Ray spectrometry Journal, Vol.44, Issue 3, page 154-162, May/June 2015; Gil M. et al, Microscopy and Microanalysis of an extreme case of salt and biodegradation in 17th century wall paintings. Microscopy and Microanalysis Journal, Vol21, June2015, pp.606-616; Gil, M., Microanalytical study of the fresco “the Good and the bad judge” in the medieval village of Monsaraz (Southern Portugal). X-Ray spectrometry journal, Vol.42, Issue 4, July/August 2013, 242-250; Gil, M. et al, Analysis of paint layers color differences within a 17th century mural painting workshop in Southern Portugal by Spectra-colorimetry and SEM-EDS. Colour Research and Application, Vol39, Issue4, June2014, 288-306.

5 Serrão V., Os focos de pintura mural da Santa Casa da Misericórdia de Montemor-o-Novo (séculos XVII-XVIII) in A Misericórdia de Montemor-o-Movo, História e Património. Montemor-o-Novo, Santa Casa da Misericórdia de Montemor-o-Novo, 200, pp.147-172.

6 Piovesan, R., Mazzoli C., Maritan L., and Cornale,P, « Fresco and Lime-Paint: an experimental study and objective criteria for distinguishing between these painting techniques» Archeometry, 54 (4), 2012, 723-736.

7 Cornell, R.M., Schwertmann U., The Iron oxides: structure, properties, reactions, occurences and uses (2nd edn) -Wiley-VCH GmbH&Co.KGaA, Weinheim, 2003.

8 Renzoni M., «Sull’ uso della tempera nella techniche ad afresco», KERMES, 30, 1997, 3-10.

List of illustrations

Title Fig 1 - Overall view of the decorative cycle:1-Estio;2- June; 3- Autumn; 4- Winter; 5- May; 6- Summer; 7- September; 8- April; 9- October?; 10- August; 11- November; 12- July; 13- April; 14- December; 15- Wind; 16-February; 17-Water;18- Fire; 19- January; 20- Earth.
Credits (photos Manuel Ribeiro 2013)
URL http://books.openedition.org/cidehus/docannexe/image/2198/img-1.jpg
File image/jpeg, 136k
Title Table I - Mineralogical composition by X-ray diffraction
URL http://books.openedition.org/cidehus/docannexe/image/2198/img-2.jpg
File image/jpeg, 148k
Title Fig 2 - Details of the painting technique in racking light
Credits (Photo Manuel Ribeiro 2013)
URL http://books.openedition.org/cidehus/docannexe/image/2198/img-3.jpg
File image/jpeg, 104k
Title Fig 3 - Details of the under drawings made free hand by brush with red ochre’s
Credits (photo Manuel Ribeiro 2013)
URL http://books.openedition.org/cidehus/docannexe/image/2198/img-4.png
File image/png, 998k
Title Fig 4 - OM and SEM images of paint layers. The rows indicate the presence of the carbonation line at the interface of the mortars with the paint layers
URL http://books.openedition.org/cidehus/docannexe/image/2198/img-5.jpg
File image/jpeg, 129k

Author(s)

UÉ, HERCULES

Milene Gil é especialista em pinturas murais na vertente da conservação e restauro e do seu estudo científico. Faz parte, com Joana Costa, Luís Dias, António José Candeias e José Mirão, de um grupo de investigadores das técnicas, suportes e cultura material do património que vêm marcando diferença nas suas conclusões e propostas de intervenção resultantes do seu domínio de saberes como a química e outras ciências aplicadas

UÉ, HERCULES

Faz parte com Milene Gil - especialista em pinturas murais na vertente da conservação e restauro e do seu estudo científico-, Luís Dias, António José Candeias e José Mirão, de um grupo de investigadores das técnicas, suportes e cultura material do património que vêm marcando diferença nas suas conclusões e propostas de intervenção resultantes do seu domínio de saberes como a química e outras ciências aplicadas.

UÉ, HERCULES

Faz parte com Milene Gil - especialista em pinturas murais na vertente da conservação e restauro e do seu estudo científico-, Joana Costa, António José Candeias e José Mirão, de um grupo de investigadores das técnicas, suportes e cultura material do património que vêm marcando diferença nas suas conclusões e propostas de intervenção resultantes do seu domínio de saberes como a química e outras ciências aplicadas.

UÉ, HERCULES

Faz parte com Milene Gil - especialista em pinturas murais na vertente da conservação e restauro e do seu estudo científico-, Joana Costa, Luis Dias e José Mirão, de um grupo de investigadores das técnicas, suportes e cultura material do património que vêm marcando diferença nas suas conclusões e propostas de intervenção resultantes do seu domínio de saberes como a química e outras ciências aplicadas.

UÉ, HERCULES

Faz parte com Milene Gil - especialista em pinturas murais na vertente da conservação e restauro e do seu estudo científico-, Joana Costa, Luis Dias e António José Candeias, de um grupo de investigadores das técnicas, suportes e cultura material do património que vêm marcando diferença nas suas conclusões e propostas de intervenção resultantes do seu domínio de saberes como a química e outras ciências aplicadas.

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