10.6092/issn.1973-9494/1407
The oil paintings and “Prayer of Tobias and Sarah” and “The Archangel Raphael reveals himself to
Tobi and his son Tobias”, executed by Francesco Bruno at the end of the XVIII century on oval
Conservation Science in Cultural Heritage
210
shaped canvas, were investigated by integrated physica-chemical and analytical methodologies in
order to obtain scientific data capable of elucidating the state of conservation and the painting technique.
Optical (OM) and electronic (SEM-EDS) microscopy, micro-FT-IR spectroscopy, were applied on
some microfragments whilst the two whole paintings were analyzed by the non invasive IR reflectografy
technique.
The reflectography evidenced some pentimenti of author on the canvas “Prayer of Tobias and
Sarah”, while invasive analysis made it possible to locate the stratigraphic sequence of each canvas
and to characterise the constituent materials.
application/pdf
1973-9494
1407
en
Silvestro Antonio Ruffolo
Conservation Science in Cultural Heritage
The polychrome works “Prayer of Tobias and Sarah” and “The Archangel Raphael reveals himself to Tobi and his son Tobias”, inside the Cathedral of Cosenza: diagnostic investigations and considerations on the conditions of conservation
Text.Serial.Journal
https://conservation-science.unibo.it/
8
Articles
2009-04-17
2008-04-17
2015-11-02
199-211
CSCH
Silvestro Antonio Ruffolo
2008
10.6092/issn.1973-9494/1407
199
1973-9494
en
211
The polychrome works “Prayer of Tobias and Sarah” and “The Archangel Raphael reveals himself to Tobi and his son Tobias”, inside the Cathedral of Cosenza: diagnostic investigations and considerations on the conditions of conservation
https://conservation-science.unibo.it/article/download/1407/776
8
T
    HE POLYCHROME WORKS “PRAYER OF TOBIAS AND SARAH”
    AND “THE ARCHANGEL RAPHAEL REVEALS HIMSELF TO TOBI
    AND HIS SON TOBIAS”, INSIDE THE CATHEDRAL OF COSENZA:
    DIAGNOSTIC INVESTIGATIONS AND CONSIDERATIONS
    ON THE CONDITIONS OF CONSERVATION

Gianluca Nava
Laboratorio “Nova Ars Restaurandi”, Cosenza
Cesare Oliviero-Rossi, Giuseppe Antonio Ranieri
Dipartimento di Chimica, Università della Calabria
Silvestro Antonio Ruffolo
Dipartimento di Scienze della Terra, Università della Calabria




1. Introduction

    The restoration of the paintings Prayer of Tobias and Sarah and The Archangel
Raphael reveals himself to Tobi and his son Tobias, has offered the opportunity to lead
a major scientific investigation to obtain information on materials used by the author.
These paintings are Calabrian works of eighteenth century, kept in the cathedral of
Cosenza.




                                                                                           Conservation Science in Cultural Heritage, 8/2008
    The origins Cathedral of
Cosenza are unknown. It
was destroyed by an earth-
quake and the rebuilding
was started in 1185 on the
Pancrazio Hill. It was com-
pleted by 1222 when the
Duomo was consecrated by
Emperor Frederick II. In the
first half of the 18th century it
was covered by a baroque
superstructure which obliter-
ated the original structure
and its works of art. At the        Figure 1. The facade of Cathedral of Cosenza.

                                                                                          199
                                                                                                   end of the 19th century, Archbishop Camillo Sorgente entrusted the work to Giuseppe
                                                                                                   Pisanti, who recovered the original old arches and the ancient structure of the church (fig.
                                                                                                   1). In the Cathedral there is the tomb of the Queen Isabella d’Aragona, wife of the French
                                                                                                   King Philip III. In the Treasury of the adjacent Archbishops Palace is the rare and pre-
                                                                                                   cious Stauroteca (Byzantine Cross) of the emperor Frederick II. It was a gift of the
                                                                                                   Emperor Frederick II to the Cathedral upon consecration [1-5].
                                                                                                      The purpose of this study was to obtain a physical-chemical description of the organ-
                                                                                                   ic and inorganic compounds, the stratigraphic sequence, the pigments and binders used
G. Nava et al. - The polycrome works “Prayer of Tobias and Sarah” and “The Archangel Raphael...”




                                                                                                   in these paintings to clarify the execution technique of the paintings, their state of con-
                                                                                                   servation and the aging process. Such a survey thus offered an appropriate Scientific tool
                                                                                                   useful for carrying out a proper restoration.
                                                                                                      The works “Prayer of Tobias and Sarah” and “The Archangel Raphael reveals him-
                                                                                                   self to Tobi and his son Tobias” are two oil paintings on oval shaped canvas and having
                                                                                                   size 120 × 77 cm. They were attributed by Favorita Iannace of the Calabrian
                                                                                                   Superintendent for Etnoantropologico Artistic and Historical Heritage (PSAE) to
                                                                                                   Calabrian painter Francesco Bruno. The works depict episodes from the life of Tobias,
                                                                                                   the protagonist of the homonymous deuterocanonico book of Sacred Sriptures to which
                                                                                                   is dedicated an entire cycle of works attributed to the same Bruno and that is kept in the
                                                                                                   Cathedral of Cosenza.
                                                                                                      The paintings are placed inside the chapel of the Most Holy Sacrament and located
                                                                                                   behind the left nave of the cathedral, more precisely between the chapel dedicated to the
                                                                                                   city protector, Madonna of Pilerio, and the sacristy.




                                                                                                                                                                          Figure 2. “Prayer of
                                                                                                                                                                          Tobias and Sarah”:
                                                                                                                                                                          initial state (on the
                                                                                                                                                                          left) and final state
                                                                                                                                                                          (on the right).

                         200
Figure 3. “The Arc-
hangel        Raphael
reveals himself to
Tobi and his son
Tobias”: initial state
(on the left) and final
state (on the right).

   The paintings are shown in figures 2 and 3.
   The paintings as far as formal, style, color and iconographic relations are concerned
they perfectly reflect the productive artistic of cultural ambient they relate to. As regards
the lighting balance, Bruno shows a wise use of the palette with careful attention to
details related to a meticulous representation of perimeter ornaments of garments. This
is the case of the details in the two paintings
when Bruno expresses a good level of the pin
traits and garment embroidery of both figures
representing the Archangel and the embroidery
executed on the board as Sarah’s garment. Even
the drapery nuances symbolize quantity of their
volumes.                                                                                          Conservation Science in Cultural Heritage
   The chapel, built in 1689, belonged to the
“Archiconfraternity of Oration and Death”, as
evidenced by the emblem with the skull placed
at the centre of the apse arch. It is shown in fig.
4. The current state of the chapel is not the
original one: it was rebuilt in 1756 and restruc-
tured in Baroque style. It is more likely that
most of the chapel artistic works were made in
                                                      Figure 4. Picture of Chapel of
this period.                                          “Archiconfraternity of Oration and
   The central altar, made in polychrome marble       Death”.

                                                                                                201
                                                                                                   Neapolitan Baroque style, was erected in 1771. Such date is carved at the base of the
                                                                                                   altar itself, which shows similarities for the formal, stylistic and iconographic traits with
                                                                                                   that of the contiguous chapel of the Pilerio.
                                                                                                      On the apse side walls two canvases are placed. One is placed on the left of the altar
                                                                                                   and it represents “The Archangel Raphael with Tobias in the act of cutting a fish”. It is
                                                                                                   dated eighteenth century and attributed to F. Bruno. A second canvas is placed on the
                                                                                                   right of the altar and depicts “Tobi who drags a dead man to burial”. It is signed by F.
                                                                                                   Bruno A.D. 1765.
G. Nava et al. - The polycrome works “Prayer of Tobias and Sarah” and “The Archangel Raphael...”




                                                                                                      On the vault of the apse is painted The Pietà. It is dated eighteenth century and by
                                                                                                   unknown author. On the vault of the nave there is a large eighteenth century canvas
                                                                                                   depicting a scene from the second book of Maccabees, where the inscription “Sancta et
                                                                                                   salubris east cogitatio pro defunctis exorare ut to peccatis solvatur” is reported [6]. On the
                                                                                                   sides of the aisle, placed against the walls, finely carved and decorated are arranged the
                                                                                                   stalls, works by masters of Cosenza of that century, where the brothers used to sit.
                                                                                                   Attributed to the same hands is the pulpit at the right of the altar [7].
                                                                                                      On the walls behind the stalls four oval canvases are placed: two on the left looking
                                                                                                   at the altar, depict “Tobi regains his sight” and “Prayer of Tobias and Sarah”, the other two
                                                                                                   canvases on the right depict “The Archangel Raphael reveals himself to Tobi and his son
                                                                                                   Tobias” and “The Return of Tobias”.
                                                                                                      A documentary search – about two paintings that are the subject of our discussion –
                                                                                                   was conducted at the Archive of the Superintendence for Architectural Heritage and
                                                                                                   Landscape of Calabria, seat of Cosenza, and has led to the discovery of two photos of
                                                                                                   1973 that testify the execution of a previous restoration.
                                                                                                      It was necessary to realize a new photographic documentation to define the conser-
                                                                                                   vation state of the works before the restoration intervention. The paintings showed an
                                                                                                   advanced state of deterioration that has made it necessary a marked recovery interven-
                                                                                                   tion. At an first visual inspection the canvases appeared to be damaged in both the pro-
                                                                                                   tective film, which was uneven and oxidized, and in the pictorial layer, that was charac-
                                                                                                   terized by exfoliation, fragmentation, vacancies and by the typical craquelure structure.

                                                                                                   2. Experimental section

                                                                                                      Infrared reflectograms were taken using a 2.0 Mpixel system multiple IR and UV high
                                                                                                   resolution DG 1 multispectral instrument equipped with a precision TV infrared camera
                                                                                                   and a NIKON F1,2:50 mm lens, in front of which an interference filter at was placed.
                                                                                                   Image capture and digitisation procedure was controlled through special software.

                                202
  Table 1. Legenda of the samples taken out of the painting: “The Archangel
  Raphael reveals himself to Tobi and his son Tobias”.

   Sample                                Sample description

             Blue coloured micro-fragment taken from the inferior part of the garment of
    CPA1
             the Archangel Raffaele

    CPA2     Flesh-colour micro-fragment taken the right arm of the Archangel Raffaele

    CPA3     Micro-fragment taken from o cloud

    CPA4     Red coloured micro-fragment taken from the garment of Tobia



   IR reflectography exploits the characteristic of infrared frequency radiation to cross
the painting surface layers; it thus has the possibility to investigate the layer immediately
underneath the pictorial film and bring to light the preparatory drawing or any second
thoughts [8, 9].
   Micro collecting was carried out on the two works in the areas that showed higher signs
of degradation and thus where it was easier to remove fragments for the laboratory sur-
vey. The legenda of the drawings made on the two works is shown in tables 1 and 2.
   The IR analysis on the samples were made using the FT-IR Jasco 4200 spectrome-
ter with a maximum resolution of 0.5 cm-1 and signal noise 30000/1. The IR spectroscopy
is an analytical technique used frequently enough to characterize the materials coming
from the works of art, especially the compounds of organic origin [10]. In our case it has
been used successfully, providing valuable information regarding the materials and tech-
niques used by the artist.
   Some of the fragments taken were observed after embedding in resin and cut, in                 Conservation Science in Cultural Heritage


 Table 2. Legenda of the samples taken out of the painting: “Prayer of Tobias and
 Sarah”.

   Sample                                   Sample description

    CPB1      Green coloured micro-fragment taken from the garment of Tobia

    CPB2      Red coloured micro-fragment taken from the garment of Tobia

    CPB3      Black coloured micro-fragment taken from the background

    CPB4      Blue coloured micro-fragment taken from the garment of the Archangel Raffaele



                                                                                                203
                                                                                                   cross section, in order to describe the stratigraphic sequence. The analysis was carried
                                                                                                   out through a Leica MZ 12.5 stereoscopic system operating in reflected light. Scanning
                                                                                                   electron microscope (SEM) analysis was carried out to obtain morphological and chemi-
                                                                                                   cal data. The apparatus was an Esem Quanta 200 by Fei/Philips coupled with an energy
                                                                                                   dispersive X-ray spectrometer (EDS). EDS microanalysis was performed in order to
                                                                                                   obtain information on the elemental compositions of the samples [11-12].

                                                                                                   3. Results and discussions
G. Nava et al. - The polycrome works “Prayer of Tobias and Sarah” and “The Archangel Raphael...”




                                                                                                      IR reflectography investigations were carried out on significant portions of the two
                                                                                                   paintings. For each portion were used IR filters 715, 830 and 1000 nm. Two evidences of
                                                                                                   Bruno pentimenti have been identified on the painting “Prayer of Tobias and Sarah” on the
                                                                                                                                                                   Archangel Raphael right
                                                                                                                                                                   foot and right shoulder
                                                                                                                                                                   respectiely.
                                                                                                                                                                       Visible    light    and
                                                                                                                                                                   Infrared Images of the
                                                                                                                                                                   painting details are shown
                                                                                                                                                                   in figures 5 and 6 where
                                                                                                                                                                   the pentimenti are present.
                                                                                                                                                                   In the images concerning
                                                                                                                                                                   the detail of the Archangel
                                                                                                   Figure 5. Image in visible light (on the left) and IR (on the   Raphael right shoulder it is
                                                                                                   right) of the particular of the Archangel’s shoulder.           clear the initial pentimento
                                                                                                                                                                   of the artist in the prepara-
                                                                                                                                                                   tory phase being possible
                                                                                                                                                                   to observe in the image col-
                                                                                                                                                                   lected in IR, the presence
                                                                                                                                                                   of a riser on the Archangel
                                                                                                                                                                   shoulder that disappears in
                                                                                                                                                                   the final painting.
                                                                                                                                                                       The IR image of the
                                                                                                                                                                   Archangel Raphael foot
                                                                                                                                                                   shows how the artist’s
                                                                                                   Figure 6. Image in visible light (on the left) and IR (on the   repentance was con-
                                                                                                   right) of the particular of the Archangel’s foot.               ducted on the same pic-

                           204
    Figure 7. IR spectrum relative to the sample CPA3.


torial drawing. It is hardly observable with the naked eye. The pentimento is character-
ized by a translation of the Archangel right foot and the IR image proves how the artist
had reduced the lower part of the Archangel figure.
   A fragment of the CPA3 sample was analyzed by FT-IR spectroscopy. In the spectrum,
shown in figure 7, are distinguishable the stretching of methyl groups (2930 cm–1 and
2850 cm–1) which indicate the presence of organic matter, the characteristic frequencies
of calcite (1400 cm–1 and 890 cm–1), the intense band related to silicates located at 1000
cm–1 and finally the signals typical of the whewellite Ca (C2O4) (H2O), an hydrated miner-
al of the calcium oxalate, a typical product of the organic matter degradation [13-14].
   It is noteworthy that the absence of signals relating to amines and gypsum. This result
excludes that the preparation was made through the traditional mixture of gypsum and           Conservation Science in Cultural Heritage
animal glue.
   The FT-IR analysis is unable to provide further information about the organic com-
pounds present as the frequency characteristics of the various compounds are “masked”
by the absorption of inorganic materials. Through the observation of cross-section by an
optical microscope in reflected light at 100X magnification (fig. 8), it was conducted the
stratigraphic analysis of the paintings that made it possible to locate the following
sequence of layers:
1) light brown coloured canvas fraction;
2) yellow preparation layer with variable granulometry having thickness between 100
   and 300 mm;

                                                                                             205
                                                                                                                                                          3) pictorial layer having variable
                                                                                                                                                              thickness between 40 and 130
                                                                                                                                                              µm;
                                                                                                                                                          4) thin layer of brownish coloured
                                                                                                                                                              paint.
                                                                                                                                                              All sections observed have the
                                                                                                                                                          same stratigraphic succession, but
                                                                                                                                                          differ in the nature of pigment in the
G. Nava et al. - The polycrome works “Prayer of Tobias and Sarah” and “The Archangel Raphael...”




                                                                                                                                                          pictorial layer. On cross-section
                                                                                                                                                          morphological investigations and
                                                                                                                                                          elemental analysis were carried out
                                                                                                   Figure 8. Image on the microscope of the sample
                                                                                                                                                          through the SEM microscope. The
                                                                                                   CPA2.
                                                                                                                                                          elemental analysis on the A1 sam-
                                                                                                   ple shows a high percentage of lead, while sodium, aluminum, silicon and sulphur are
                                                                                                   present in smaller quantities. Lead indicates the presence of white lead (basic lead car-
                                                                                                   bonate 2PbCO3 Pb(OH)2) while the molars relation between Na, Al, Si and S indicate the
                                                                                                   presence of Ultramarine Blue, an artificial blue pigment similar to lapislazuli.
                                                                                                      The sample CPA2 is essentially composed of lead, while in smaller quantities are
                                                                                                   present sodium, magnesium, aluminum, silicon, chlorine, potassium, calcium and iron.
                                                                                                   As for the sample CPA1, lead indicates white lead pigments, while the presence of Al,
                                                                                                   Si and Fe individuates Yellow Ochre which are pigments of mineral origin consisting of
                                                                                                   silica, silica-alumina compounds and iron oxides, used for the preparation of the flesh-
                                                                                                   colour [15].
                                                                                                      This is due to the modest quantities, which are not well recognizable by the instru-
                                                                                                   ment. However, it can be assumed that in preparing the flesh-colour it has been also used
                                                                                                   the Cinnabar pigment. The elemental analysis on the CPA4 sample highlights the pres-
                                                                                                   ence of mercury and sulphur and, on the basis of their molar relation indicates the pres-
                                                                                                   ence of Cinnabar. In the CPB1 sample the presence of white lead is found, while molars
                                                                                                   relations between Mg, Al, Si, K and Fe indicate the presence of Terra Verde; a pigment
                                                                                                   of mineral origin composed of a mixture of two- silica-alumina Fe (II) Mg and K.
                                                                                                      In the sample CPB3 the presence of white lead is not found, the percentage compo-
                                                                                                   sition of the items listed in the table (tab. 3) cannot be related to specific pigments. The
                                                                                                   high peak related to carbon in the EDS spectrum, despite it is not quantitative, suggest
                                                                                                   the presence of an organic or carbonic pigment such as graphite or Flame Black. In the
                                                                                                   pictorial layer of the sample CPB4 it has been found the presence of white lead and

                            206
Table 3. Summary table of the analyses carried out through SEM-EDS (the compositions
are expressed as molar percentage).

                                                                                      Pigment
Localization    Al      Si    P      S      Pb      Cl    Hg     Ca     Na    Fe
                                                                                    identification
                                                                                    Lead white,
A1, pictorial
                5.3    15.3   –     7.5    62.7     1.3    –     4.8    3.1   –     Ultramarine
layer
                                                                                        Blue
                                                                                    Lead white,
A2, pictorial
                2.5    10.8   –     7.6    59.1     1.7   1.1    4.7    4.2   4      Cinnabar,
layer
                                                                                    yellow Ochre
A4, pictorial                                                                       Lead white,
                4.7    14.1   –     19.6    4.7     7.1   16.6   16.6   8     2.7
layer                                                                                Cinnabar
B1, pictorial                                                                       Lead white,
                6.2    11.9   –      –     22.3     3.2    –     36     –     2.4
layer                                                                               Terra Verde
                                                                                      Organic
B3, pictorial
                9.3    35.9   0.8    –      4.5      –     –     29     –     8.3    brownish
layer
                                                                                      pigment
                                                                                    Lead white,
B4, pictorial
                16.5   25.8   –      –      27      3.5    –      8     –     5.9   Ultramarine
layer
                                                                                        Blue


Ultramarine Blue. The pigments identified by SEM-EDS in the various samples are sum-
marised in tab. 3.
   For the morphological analysis of the preparation, samples CPA1 and CPB1 were
taken into consideration as represen-
tative of both works. In both them, the
SEM and SEM-EDS techniques have
revealed a carbonatic fine grain matrix                                                                Conservation Science in Cultural Heritage
preparation (fig. 9). It is also possible
to note mineral crystals, microfossils
and plant material even through visual
analysis.

4. Conclusions

   The diagnostic investigations car-
ried out on paintings have helped to
highlight some elements of the author             Figure 9. Image on the SEM of the sample
technical executive either through non-           CPB1 at 600X.

                                                                                                     207
                                                                                                   invasive methods or invasive. The reflectography highlighted some repentances on the
                                                                                                   canvas Prayer of Tobias and Sarah, while invasive analysis made it possible to locate the
                                                                                                   stratigraphic sequence of each canvas and to characterise the constituent materials. The
                                                                                                   preparatory layer presents a carbonate matrix with clusters of siliceous nature, microfos-
                                                                                                   sils and plant material. The pigments used in the pictorial layer are ultramarine blue,
                                                                                                   cinnabar, green earth, yellow ochre and white lead. The latter pigment was abundantly
                                                                                                   used for the preparation of almost all pictorial sections.
                                                                                                      The synergy between the various professionals within the team that performed the
G. Nava et al. - The polycrome works “Prayer of Tobias and Sarah” and “The Archangel Raphael...”




                                                                                                   work of conservation and restoration, has helped to achieve a good result. On this pur-
                                                                                                   pose it was necessary to duly consider all the complex variables deriving from the recog-
                                                                                                   nition of the constituent materials of the works under consideration.
                                                                                                      In such way, it is possible to make a re-establishment of “art work system” consider-
                                                                                                   ing all its peculiarities, including those related to the choices made by the author at the
                                                                                                   time of its conception, the reflection of the time distinctive characters, and the knowledge
                                                                                                   of their inevitable interaction. The use of products and techniques in intervention, in fact,
                                                                                                   takes into account the future actions that can intervene on such artefacts.
                                                                                                      This consciousness has oriented certain branches of conservation theory. Today, one
                                                                                                   of the main challenges is perhaps posed by the pervasive idea that, while conservation
                                                                                                   works “for the future” – and on this base the criteria of minimum intervention, reversibili-
                                                                                                   ty, recognizability, have been developed – interpretation is “for the present”. This
                                                                                                   approach has influenced the development and application of criteria like consensus,
                                                                                                   inclusiveness and accuracy.
                                                                                                      The axioms of recognizability, reversibility and minimum intervention were the exclu-
                                                                                                   sive and founding peculiarity of the use of techniques and materials [16]. These actions
                                                                                                   were of course, envisaged also for those conditions unfit for their proper conservation,
                                                                                                   inside the places of worship for which the works were conceived. The temperature and
                                                                                                   relative humidity parameters in the chapel dedicated to Death and Prayer in the Cathedral
                                                                                                   of Cosenza, as it happens in most places of worship in our country, are not suitable for
                                                                                                   the proper conservation of the artistic artefacts in general. The interventions perspective
                                                                                                   and feasible techniques to keep in optimum such parameters for the conservation of art
                                                                                                   works, is very broad and diversified. As far as we know, instead of reclaiming by using
                                                                                                   de-humidifiers, it could be of great help to adopt such passive remedies as insulation
                                                                                                   through windows that guarantee a higher isolation of indoor environments. It is therefore
                                                                                                   important to solve this problem that has long been debated by the whole scientific com-
                                                                                                   munity of the international restoration.

                            208
Bibliography
[1] BORRETTI M. 1933, La Cattedrale di Cosenza. Monografia storico-artistica,
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[2] RUSSO F. 1956, Storia dell’arcidiocesi di Cosenza, Napoli, Rinascita artistica.
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[10] DERRICK M.R., STULIK D., LANDRY J.M. 1999, Infrared Spectroscopy in
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Summary
The oil paintings and “Prayer of Tobias and Sarah” and “The Archangel Raphael reveals himself to
Tobi and his son Tobias”, executed by Francesco Bruno at the end of the XVIII century on oval

                                                                                                   209
                                                                                                   shaped canvas, were investigated by integrated physica-chemical and analytical methodologies in
                                                                                                   order to obtain scientific data capable of elucidating the state of conservation and the painting tech-
                                                                                                   nique.
                                                                                                   Optical (OM) and electronic (SEM-EDS) microscopy, micro-FT-IR spectroscopy, were applied on
                                                                                                   some microfragments whilst the two whole paintings were analyzed by the non invasive IR reflec-
                                                                                                   tografy technique.
                                                                                                   The reflectography evidenced some pentimenti of author on the canvas “Prayer of Tobias and
                                                                                                   Sarah”, while invasive analysis made it possible to locate the stratigraphic sequence of each canvas
                                                                                                   and to characterise the constituent materials.


                                                                                                   Riassunto
G. Nava et al. - The polycrome works “Prayer of Tobias and Sarah” and “The Archangel Raphael...”




                                                                                                   Le opere “Preghiera di Tobia e Sara”, “L’Arcangelo Raffaele si rivela a Tobi e a suo figlio Tobia” sono
                                                                                                   due dipinti olio su tela di forma ovale ed aventi dimensioni cm 120 × 77, attribuiti al pittore calabre-
                                                                                                   se Francesco Bruno (XVIII secolo). Le opere raffigurano episodi della vita di Tobia a cui è dedicato
                                                                                                   uno intero ciclo di opere attribuite allo stesso artista e custodite nel duomo di Cosenza.
                                                                                                   L’articolo raccoglie l’analisi diagnostica dello stato di conservazione delle opere prima dell’interven-
                                                                                                   to di restauro, effettuata mediante l’utilizzo di diverse tecniche chimico-fisiche ed inoltre alcuni cenni
                                                                                                   sulla metodologia d’intervento. Lo scopo di questo studio è stato quello di ottenere una descrizione
                                                                                                   chimico-fisica dei composti organici ed inorganici, la sequenza stratigrafica, i pigmenti impiegati e i
                                                                                                   leganti utilizzati in queste opere pittoriche per chiarire la tecnica di esecuzione dei dipinti, il loro stato
                                                                                                   di conservazione e il processo di invecchiamento. Tale indagine ha quindi offerto un appropriato
                                                                                                   mezzo scientifico utile per la corretta esecuzione del restauro.


                                                                                                   Résumé
                                                                                                   Les oeuvres “Preghiera di Tobia e Sara”, “L’Arcangelo Raffaele si rivela a Tobi e a suo figlio Tobia”
                                                                                                   sont deux peintures à huile sur toile de forme ovale et ayant des dimensions 120 x 77cm, attribuées
                                                                                                   au peintre calabrais Francesco Bruno (XVIIIème siècle). Les oeuvres représentent des épisodes de
                                                                                                   la vie de Tobia auquel est consacré un cycle entier d’œuvres attribuées au même artiste et gardée
                                                                                                   dans le dôme de Cosenza.
                                                                                                   L’article recueille l’analyse diagnostique de l’état de conservation des oeuvres premières de l’inter-
                                                                                                   vention de restauration, effectuée moyennant l’utilisation de diverses techniques chimico-physiques
                                                                                                   et, en outre, quelques aperçus sur la méthodologie d’intervention. Le but de cette étude a été celui
                                                                                                   d’obtenir une description chimico-physique des composés organiques et inorganiques, la séquence
                                                                                                   stratigraphique, les pigments employés et les liants utilisés dans ces oeuvres picturales pour clari-
                                                                                                   fier la technique de réalisation des peintures, leur état de conservation et le processus de vieillisse-
                                                                                                   ment. Cette recherche a donc offert un approprié moyen scientifique utile pour la correcte réalisa-
                                                                                                   tion de la restauration.


                                                                                                   Zusammenfassung
                                                                                                   Die Werke “Gebet von Tobias und Sarah” und “Der Erzengel Raphael offenbart sich dem Tobit und
                                                                                                   seinem Sohn Tobias” sind zwei Ölgemälde auf einer ovalen Leinwand, mit Größe 120 x 77 cm, die
                                                                                                   dem kalabrischen Maler Francesco Bruno (XVIII. Jahrhundert) zugeschrieben sind. Die Werke stel-
                                                                                                   len einige Episoden aus dem Leben von Tobias dar, dem ein ganzer Zyklus von Werken gewidmet
                                                                                                   ist. Solche Werken sind dem selben Maler zugeschrieben und sind im Dom in Cosenza verwahrt.
                                                                                                   Der Artikel berichtet über die diagnostische Analyse des Erhaltungszustands der Werke vor dem
                                                                                                   restauratorischen Eingriff, bei dem verschiedene chemische-physikalische Techniken angewendet
                                                                                                   wurden. Außerdem deutet der Artikel kurz auf die Methodologie des Eingriffs an. Das Ziel dieser
                                                                                                   Studie war es, eine chemische-physikalische Beschreibung der organischen und anorganischen
                                                                                                   Verbindungen zu haben, zusammen mit Informationen über die stratigraphische Sequenz, die ange-
                                                                                                   wendeten Pigmenten und die Bindemittel dieser malerischen Werke, um die Technik der Gemälde,

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deren Erhaltungszustand und den Alterungsprozess zu erklären. Diese Untersuchung stellt also ein
geeignetes wissenschaftliches Mittel für die korrekte Durchführung der Restaurationsarbeiten dar.


Resumen
Las obras “Oración de Tobías y Sara”, “El Arcángel Rafael se revela a Tobi y a su hijo Tobías” son
dos pinturas al óleo sobre lienzo, de forma oval y con unas medidas de 120 × 77 cm, atribuidas al
pintor calabrés Francesco Bruno (siglo XVIII). Las obras representan episodios de la vida de Tobías,
a quien se dedica un ciclo completo de obras atribuidas al mismo artista y conservadas en la cate-
dral de Cosenza.
El artículo recoge el análisis diagnóstico del estado de conservación de las obras antes de la actua-
ción restauradora, efectuada mediante el uso de distintas técnicas químico-físicas, incluyendo ade-
más algunas datos sobre la metodología de intervención. La finalidad de este estudio ha sido la de
obtener una descripción químico-física de los compuestos orgánicos e inorgánicos, la secuencia
estratigráfica, los pigmentos empleados y las sustancias ligantes utilizadas en estas obras pictóri-
cas para aclarar la técnica de ejecución de las pinturas, su estado de conservación y el proceso de
envejecimiento. Este estudio ha ofrecido un medio científico apropiado y útil para la correcta ejecu-
ción de la restauración.




                                                                                                          Conservation Science in Cultural Heritage




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