Michelangelo Buonarroti: il restauro degli affreschi della volta e del Giudizio della Cappella Sistina
10.6092/issn.1973-9494/7166
L’ultimo restauro degli affreschi di Michelangelo in Cappella Sistina è stato diretto e condotto da personale interno ai Musei Vaticani dal giugno 1980 all’aprile 1994. L’importanza storica di questo restauro sta nel recupero dell’imprevedibile cromia michelangiolesca occultata per secoli da polvere, fumo nero e grasso di ceri e bracieri, da colla animale, gommoresine e fiele di bue dati dai restauratori del passato come ravvivanti dei colori. L’importante risultato si è potuto ottenere in completa sicurezza grazie ai progressi fatti nel campo delle metodiche e dei materiali, al forte sviluppo della diagnostica, e alla elaborazione di una teoria del restauro (C. Brandi 1950) che ancora oggi fa da supporto agli orientamenti tecnico-scientifici del restauro. La buona conservazione degli affreschi della Cappella è affidata ad un impianto di filtraggio e condizionamento d’aria rinnovato e potenziato nel 2015, e ad una moderna illuminazione a LED attivata nello stesso anno. La pulitura degli affreschi, che si sono conservati quasi perfettamente grazie alla tecnica di Michelangelo, ha permesso di studiare il modo di dipingere dell’artista e di scoprire che alcuni caratteri della tecnica della scultura in marmo sono stati da lui riprodotti in pittura, o novità assolute come la tecnica per dare tridimensionalità alle figure o le pennellate che anticipano il divisionismo e il puntinismo.
application/pdf
1973-9494
7166
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Gianluigi Colalucci
Conservation Science in Cultural Heritage
Michelangelo
Michelangelo Buonarroti: Restoration of the Frescoes on the Vaulted Ceiling and the Last Judgment in the Sistine Chapel
Text.Serial.Journal
https://conservation-science.unibo.it/
16
Articles
2017-07-24
2017-07-17
2017-07-24
2017-09-04
89-126
CSCH
Gianluigi Colalucci
2016
10.6092/issn.1973-9494/7166
89
Conservazione e Restauro S.n.c., Rome
1973-9494
Michelangelo
en
126
Mancinelli, F., Colalucci, G., Morresi, F., Gabrielli, N., Borrelli, E., Cerri, F., Giovannone, C., Laurenzi Tabasso, M., Falcucci, C., Sciuti, S., Montacutelli, R., Tarsitani, G., Moggi, O., Fara, G.M., Chiari, G., Burragato, F., Ballirano, P., Maras, A. (1999) Michelangelo, La Cappella Sistina, documentazione e interpretazioni - Rapporto sul restauro del Giudizio Universale, 2 volumes. Novara: Musei Vaticani - Istituto Geografico De Agostini.
Michelangelo Buonarroti: Restoration of the Frescoes on the Vaulted Ceiling and the Last Judgment in the Sistine Chapel
https://conservation-science.unibo.it/article/download/7166/6891
16
M     ICHELANGELO BUONARROTI: RESTORATION OF THE
      FRESCOES ON THE VAULTED CEILING AND THE LAST
     JUDGMENT IN THE SISTINE CHAPEL

   Gianluigi Colalucci*3
   Restorer, Conservazione e Restauro S.n.c.
   Rome, Italy

   Keywords: restoration, fresco, vault, Sistine, Michelangelo



   1. Introduction

    When restoration of Michelangelo’s frescoes in the Sistine Chapel began in June
1980, conservation, on the whole, had reached very high standards. Intervention tech-
niques had steadily evolved and the use of diagnostics had become common practice.1
    It should be remembered that in Italy, from a historical point of view, the develop-
ment of diagnostics in this field dates back to 1939, year of the foundation of the
Central Institute for Restoration, even though scientific technologies such as X-rays,
ultraviolet rays and chemical analyses, had occasionally been used in the past, espe-
cially in the examination of easel painting (movable art).
    In addition to the technical and scientific apparatus, another element of fundamen-
tal importance was Cesare Brandi’s “Il fondamento teorico del restauro”, published in
1950 in the N.1 Bulletin of the ICR - Istituto Centrale per il Restauro (Central Institute
for Restoration). In this publication, known today as the “Theory of Restoration”, he lay




                                                                                                      CONSERVATION SCIENCE IN CULTURAL HERITAGE
down a theoretical framework for restoration; it was considered a fundamental doc-
trine, which for the first time (and most importantly) dealt with the restoration of paint-
ings, in complete contrast to previous theories that had been developed by architects
exclusively for architectural restoration.
    Even today, Brandi’s theory is a handbook for younger generations, and is the doc-
trine that guided the restoration of Michelangelo’s frescoes in the Sistine Chapel. As a
result, the old concept that viewed restoration more as an aesthetic operation, which
ultimately led to the addition of materials to embellish the paintings, such as brighten-
ers, varnishes, heavy retouching and repainting, was completely overturned by the
concept of retrieving the original pictorial text. As a consequence, all material that is
foreign to the art work (except in specific cases), that is to say, anything that has been
added during past restoration work, nowadays, tends to be removed.
    Thanks to the concept of recovering the original and also to the more than fifty years
of scientific research in the field of cultural heritage, it is now possible to study in depth
the materials constituting the work of art and its execution technique.
    The case in point, the restoration of Michelangelo’s frescoes in the Sistine Chapel,
is an emblematic example. Its cleaning has helped bring to light the true colors of
Michelangelo’s masterpiece and at the same time provided a fundamental moment to


* Corresponding author: g.colalucci@virgilio.it


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                                                                                             study this work of art. Over the centuries it has undergone such severe tampering with
                                                                                             that the impression was that the ‘buon fresco’ (‘true fresco’, technique on wet plaster)
                                                                                             used to decorate the Sistine Chapel was nothing more than a ‘fresco-secco’ (fresco
                                                                                             technique on dry plaster) with unidentified variants [1].



                                                                                                2. Case study

                                                                                                2.1. The artifact

                                                                                                 The Sistine Chapel was built by Pope Sixtus IV Della Rovere on one side of the
                                                                                             Vatican hill using part of the foundations of a demolished Medieval chapel known as
G. Colalucci - Michelangelo Buonarroti: Restoration of the frescoes on the vaulted ceiling




                                                                                             the Cappella Magna. Unfortunately, the foundations were too weak to support the great
                                                                                             weight of the new building (the walls are three meters wide) and their collapse, to-
                                                                                             gether with the instability of the terrain, soon produced serious lesions in both the walls
                                                                                             and the vault, which at the time was still decorated with the star-studded sky by Pier
                                                                                             Matteo d’Amelia [2].
                                                                                                 In 1504, after the insertion of 12 iron chains on the vault and the area of the Chapel
                                                                                             foundations, which should have stopped the advance of a visible crack that stretched
                                                                                             across the vault, Pope Julius II ordered the starry sky of the vaulted ceiling to be de-
                                                                                             stroyed, and convinced – or compelled – Michelangelo to paint the huge space (1508-
                                                                                             1512).2 After some years, as a result of several warning signs and the subsequent
                                                                                             collapse of the architrave of the main entrance which, on Christmas Eve of 1522, fell
                                                                                             on the papal procession killing a guard next to Pope Adrian VI, further repair work was
                                                                                             carried out.
                                                                                                 The vault is painted to imitate a polycentric architecture whose space gives the
                                                                                             impression of real architectural breadth and depth, both in its solid parts and its voids,
                                                                                             as well as in the spatial dimension of the Last Judgment.
                                                                                                 Michelangelo abandoned his first idea of a faux decorative coffering with figures of
                                                                                             the twelve Apostles, to design a virtual form of architecture conceived as a large hall
                                                                                             open to the sky, inside which sat Prophets and Sibyls; in its breached vault, punc-
                                                                                             tuated by slender arches, appear the theophanies, visible manifestations of divinity,
                                                                                             which here, relate to episodes from the Old Testament. The small strips of sky seen at
                                                                                             the opposite ends of the vault suggest and confirm this idea. Thus, the virtual architec-
                                                                                             ture engages with the real architecture, raising it towards the sky of the vaulted ceiling.
                                                                                                 The lunettes and spandrels depict Christ’s ancestors, while the four corner penden-
                                                                                             tives depict: David and Goliath, Judith and Holofernes, the Punishment of Haman and
                                                                                             the bronze Serpent. In the center, between bronze nudes, young naked figures (the
                                                                                             ‘Ignudi’) and golden tondos, there are scenes from the Old Testament.
                                                                                                 Michelangelo’s Last Judgment (1534 -1541) was commissioned by Pope Clement
                                                                                             VII, followed by his successor Pope Paul III. It covered the whole altar wall where
                                                                                             there were two windows and other frescoes, including two lunettes by Michelangelo
                                                                                             and the altarpiece with the “Assumption of the Virgin”. Iconographically diverse from
                                                                                             all the others, the Last Judgment of the Sistine Chapel caused a great scandal due to
                                                                                             its many nudes and its iconographic interpretation, which veered towards heresy. Over
                                                                                             the centuries, it risked being destroyed several times, but fortunately, in the end went
                                                                                             no further than the order of the Council of Trent, which simply stated that the more
                                                                                             scandalous parts of the nude figures were to be covered (1564).


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   2.2. Conservation state

    The damage to Michelangelo’s frescoes derived primarily from problems associated
with the statics of the building. After installation of the 12 “chains” in 1504, Michelange-
lo painted the vault, but the collapse of the architrave in 1522 damaged several parts,
which meant the problem of structural restoration needed to be resolved once more.
    This, however, did not resolve the problem of the statics. Consequently, cracks
continued to appear in the architectural structure even after Michelangelo had finished
painting the entire vaulted ceiling to replace the previous star-studded sky. Neverthe-
less the vault, a segmental arch, did not collapse, as its compactness remained so, due
to the rubble masonry structure, or Roman method of construction, used and which at
its apex had a thickness of 80 cm. It was not until1564 however, when the building was
finally entrusted to the architects Vignola and Pirro Ligorio, that three extremely solid
buttresses were constructed against the Chapel, thus preventing its ultimate collapse.
    Because the lesions in the vault had also damaged Michelangelo’s frescoes, their
restoration was entrusted to the painter Domenico Carnevali, who redid two figures in
fresco that had been lost in the scene of Noah’s sacrifice, a small part of Adam’s hand
in the scene of the creation of man, the hand of God the father in the separation of the
land from the water, a portion of the neck of Jeremiah the prophet and the figure of the
young man behind him, as well as two figures in the pendentive showing the “Punish-
ment of Haman” and other less important parts.
    But the most visible and continuous damage over the years was due to the infil-
tration of rainwater from the roof and the endless smoke from candles, torches and
braziers which constantly rose toward the ceiling and along the walls of the Chapel,
as Wolfgang Goethe wrote on 16 February in1787, in his famous “Italian Journey”: “...
February 2nd we went to the Sistine Chapel, to attend the ceremony of the blessing
of the candles. But it was not for me, and I soon left with some friends. Indeed, I think:




                                                                                                    CONSERVATION SCIENCE IN CULTURAL HERITAGE
here are the actual candles which for three centuries have blackened these beautiful
frescoes, and here is the incense which, with such shamelessness, has not only en-
veloped the brightest sun in art, but year after year has made it darker and darker, and
will finally lead to its burial in total obscurity”.
    In this passage Goethe shows he is fully aware of the real problem of these frescoes
which had become black for reasons beyond Michelangelo’s control and contradicted
what was common opinion at that time; it was thought that this dark painting, almost
devoid of any color scheme, and believed to be the original, correctly interpreted the
myth of the tormented Michelangelo who was prey to black melancholia: a myth that
was exalted throughout the romantic period and beyond. In 1936, Biagio Biagetti3,
then director of the Painting Restoration Laboratory of the Vatican Museums, during a
campaign for the consolidation of the plaster in the vault, had already written: “If and
when I am able to work on it, it will not be too difficult for me to prove that we see the
polychromatic tones of the Sistine Chapel as though it were through a smoked glass”
(Figure 1). What misled the observer was the heavy, uneven, dark film of dust and
candle smoke, and above all the animal glue with oil, gum arabic and ox gall that had
been repeatedly applied to the frescoes by restorers in the past, mainly to hide the
white-colored salt efflorescence produced by the frequent infiltration of rainwater and
to brighten up the colors.
    The Last Judgment had also suffered much damage; some had been caused by
the ladders used to mount the canopy above the altar and some by the greasy candle


                                                                                               91
                                                                                             smoke and dust, the latter, in this case too, having caused the colors to become so
                                                                                             dark as to believe it was a monochrome painting, as shown in an interesting film docu-
                                                                                             mentary by Ragghianti from the fifties.
                                                                                                 Precisely because of the strong accumulation of soot, many attempts have been
                                                                                             made to clean the Last Judgment, which, however, have been unsuccessful, as they
                                                                                             inevitably ended with the artificial “fouling” of the clean portion. The blue sky (lapis
                                                                                             lazuli), in particular, had been damaged as a consequence of using the a secco tech-
                                                                                             nique too heavily and was subsequently the subject of a singular eighteenth century
                                                                                             cleaning operation, probably carried out using acid, perhaps with a strong base, that
                                                                                             left a large number of fine light-colored streaks on the sky which are quite evident in
                                                                                             old photographs (Figure 2). The technique of execution together with previous cleaning
                                                                                             efforts, has meant that much of the lapis lazuli, applied a secco, has been lost. As a
                                                                                             result, what has come down to us is only the preparatory color.
G. Colalucci - Michelangelo Buonarroti: Restoration of the frescoes on the vaulted ceiling




                                                                                             Figure 1. The scene of “God separating the light from the darkness” during cleaning. The
                                                                                             uncleaned part, seen as if through a smoked glass.


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                                                                                                          CONSERVATION SCIENCE IN CULTURAL HERITAGE
Figure 2. “The Last Judgment”: detail of the sky before cleaning. The light-colored streaks on the
sky are the result of an 18th century cleaning intervention.


   2.3. Censorship [3]

   Inaugurated on 31 October, 1542, the Last Judgment immediately provoked mixed
feelings among the people of the time. It was even called the “painting of a thousand
heresies” and, for this reason, was inserted by the Council of Trent, which ended in
1563, among the 33 paintings that were to be “corrected” without delay. After Michel-
angelo’s death, on February 18 in 1564, Daniele da Volterra was commissioned to
paint drapery on many of the nude figures held to be obscene. On Daniele’s death
the task was given to Girolamo da Fano, and then to Carnevali. The fierce censor-
ship was taken up once again in the eighteenth and nineteenth centuries, so that the
total number of naked figures covered by various cloths reached forty-two. Tempera
was used to paint the drapery, except for the group of Saint Blaise and Saint Cath-
erine which was repainted using fresco.4 The copy of the Last Judgment, now in the
Capodimonte Museum in Naples, painted by Venusti for Cardinal Farnese around
1549, therefore before the censorship, shows us how the figures originally appeared
(Figure 3, 4).


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G. Colalucci - Michelangelo Buonarroti: Restoration of the frescoes on the vaulted ceiling




                                                                                             Figure 3. “The Last Judgment”: “Saint Blaise and Saint Catherine” as they appear today, after
                                                                                             being censored by Daniele da Volterra.


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                                                                                                     CONSERVATION SCIENCE IN CULTURAL HERITAGE




Figure 4. Capodimonte Museum, Naples: “Saint Blaise and Saint Catherine” in Venusti’s copy as
they appeared in the original before being censored.



   3. The restoration

   3.1. The decision to intervene

   Applying the glue, in particular, was a threat to the paint film because each appli-
cation produced continuous and extremely minute tears which are a good breeding
ground for fungal microflora, harmful to pigments. That is why in June 1980, the Staff


                                                                                                95
                                                                                             of the Vatican Museums decided to intervene by performing a trial cleaning test on the
                                                                                             Eleazar lunette.5 Only after restoration of this limited portion of the vault and evaluat-
                                                                                             ing the results, as well as receiving encouragement from leading art historians and
                                                                                             the world of culture in general to continue the work, was the restoration project for
                                                                                             the entire cycle of Michelangelo’s frescoes defined. The work, which lasted 14 years,
                                                                                             was carried out by a very small team from the Paintings Restoration Laboratory of the
                                                                                             Vatican Museums.6
                                                                                                 The restoration was completed on April 8th, 1994 with a solemn Mass celebrated in
                                                                                             the Sistine Chapel by Pope John Paul II [4].

                                                                                                3.2. Vault – method of intervention
G. Colalucci - Michelangelo Buonarroti: Restoration of the frescoes on the vaulted ceiling




                                                                                                White spots of salt efflorescence occurred particularly in the area of the lunettes and
                                                                                             on the haunches of the vault where the pendentives are decorated with prophets and
                                                                                             sibyls. This continuous and recurrent phenomenon required a great many restoration
                                                                                             interventions to try to hide or at least mask the annoying white spots. This operation
                                                                                             was carried out by coating the frescoes several times with very diluted animal glue,
                                                                                             maintained in a hot or cold liquid form with the addition of a high percentage of vin-
                                                                                             egar – to which was added a small percentage of oil. Later on, gum arabic dissolved in
                                                                                             water was used for coating, also with the aim of brightening the colors. Coatings of ox
                                                                                             gall were also used for the same purpose. Due to the fading of the colors, flattening of
                                                                                             the shapes and the continuous formation of salt deposits, it had also been necessary
                                                                                             for the old restorers to darken the shadows of the drapery, as well as the shadows
                                                                                             cast behind the figures even further, using the color black. As a result, any memory of
                                                                                             the original colors was gradually lost, as well as giving rise to the formation of those
                                                                                             blackish-brown flesh tones on the frescoes, full of stains, which can still be seen in old
                                                                                             photographs (Figure 5).
                                                                                                To remove the layers of foreign substances from the surfaces painted using ‘buon
                                                                                             fresco’ the following protocol was used: solvent mixture consisting of water, carbox-
                                                                                             ymethyl cellulose, ammonium bicarbonate, sodium bicarbonate and desogen. The
                                                                                             gelatinous mixture was spread on the part to be cleaned, left to act for 3 minutes
                                                                                             (timed using a stopwatch), and then removed with a natural sponge soaked in deion-
                                                                                             ized water. After the fresco had dried it was possible to assess whether or not, and
                                                                                             to what extent, to perform a second cleaning using the same method. The cleaned
                                                                                             parts were repeatedly treated with large quantities of deionized water to remove any
                                                                                             remaining solvent.
                                                                                                Before proceeding to clean the parts painted in ‘buon fresco’, the few parts painted
                                                                                             in dry fresco, including parts of the retouching performed by previous restorers, were
                                                                                             waterproofed with Paraloid, so that the water used for the fresco did not do any dam-
                                                                                             age. These parts were subsequently dealt with in small portions, slowly removing the
                                                                                             layer of waterproofing and cleaning the surface of the pigments in dry fresco with small
                                                                                             brushes and solvent. In this way, even old retouching could be removed in a very con-
                                                                                             trolled way or preserved if deemed necessary.
                                                                                                The clean parts were not treated. Where necessary (some rare areas attacked by
                                                                                             salts), parts were treated locally with Paraloid B 72 using the C80 method which leaves
                                                                                             no acrylic resin on the surface. This method uses a solution of Paraloid B 72 at 5%,
                                                                                             removed after 24 hours with nitro thinner and distilled water according to a carefully
                                                                                             studied plan of alternation.


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                                                                                                        CONSERVATION SCIENCE IN CULTURAL HERITAGE
Figure 5. An old photograph of the Sistine Chapel before restoration. Michelangelo’s true colors
are completely hidden.


   3.3. The Last Judgment – method of intervention

    The method for cleaning the Last Judgment was different compared to that of the
vault, due to the large area of sky painted with blue lapis lazuli, prepared in ‘buon
fresco’, but then executed dry and therefore very delicate and impossible to treat with
water and even less so with the gel of the solvent mixture [5].
    Method: light cleaning with deionized water; cleaning with small natural sponge
soaked in ammonium carbonate dissolved in water; a compress of 4 sheets of Jap-
anese paper soaked in ammonium carbonate maintained for 12-15 minutes on the
interested part; removal of the compress and cleaning with ammonium carbonate.
Treatment with deionized water, only once cleaning is definitively completed (Figure 6).
    The extremely delicate sky was cleaned separately using a specific method based
on the light and sensitive manual skills of the restorer. The color of the sky was fixed
with a solution of Paraloid B72 at 2%. No final treatment was carried out on the parts
in ‘buon fresco’.


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G. Colalucci - Michelangelo Buonarroti: Restoration of the frescoes on the vaulted ceiling




                                                                                             Figure 6. “The Last Judgment”: the “Cyrenian”. One phase of the cleaning with compresses of
                                                                                             Japanese paper and ammonium carbonate.


                                                                                                3.4. Censored parts

                                                                                                During restoration of the Last Judgment, the problem arose on what action was to
                                                                                             be taken about the censored parts. In line with Cesare Brandi’s Theory of Restoration,
                                                                                             and in particular with concepts of “historical instances” and “aesthetic instances”, the
                                                                                             censored parts from the sixteenth century were preserved because they were consid-
                                                                                             ered to be of significant historical importance as they relate to a particularly important
                                                                                             period in time for the church: the Council of Trent and the Counter-Reformation [5].
                                                                                             Instead, as the censored parts from the eighteenth and nineteenth centuries were not
                                                                                             considered to be historically important, because they are not associated with any his-
                                                                                             torical moment in time, they were removed, preferring, as a general rule, the aesthetic
                                                                                             instance (Figures 7, 8).
                                                                                                In the vault, there were only two censored parts: the sex of one of Noah’s sons, and
                                                                                             the naked breast of a female figure nursing her baby in the Salmon lunette. In both
                                                                                             cases, the censored parts were removed.


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Figure 7. “The Last Judgment”: the censored figure of “Saint Andrew”, with a cloth added in the
18th century.


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G. Colalucci - Michelangelo Buonarroti: Restoration of the frescoes on the vaulted ceiling




                                                                                              Figure 8. “The Last Judgment”: the uncensored figure of “Saint Andrew”, after removing the cloth
                                                                                              added in the 18th century.



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   4. Diagnostics

   4.1. Laboratory investigations

   In the 1920s the Vatican Museums set up an Office for Scientific Research which
today provides support to the various Restoration Laboratories. It is these laboratories
that are responsible for all the investigations aimed at the study and restoration of
Michelangelo’s frescoes (over 400 cross-sections and 3,714 elemental analyses). The
analytical techniques used were: atomic-absorption spectrophotometry, observation
with optical microscope, infrared spectrophotometry, liquid chromatography and thin-
layer chromatography with corresponding sections of color, ultraviolet fluorescence
and infrared photography. External collaborators analyzed the composition of the plas-
ters, the chromatic value of the pigments, the pathogenic microorganisms on the fres-
coes and the air pollutants dispersed in the atmosphere of the Sistine Chapel.7

   4.2. Michelangelo’s colors

   Michelangelo, who in his youth had attended the workshop of Ghirlandaio, shows
thorough knowledge both in his use of the fresco technique and in his choice of pig-
ments all of excellent quality, selecting those suitable for fresco painting and discarding
any unsuitable ones. Consequently, it can be noted there is a lack of copper-based
pigments and a minimal use of lead-based pigments. The color range is as follows:
   – ‘bianco di San Giovanni’ (a white obtained using air-dried hydrated lime which is
     then ground; the procedure is repeated at least three times);
   – vine black;
   – ivory black;
   – mars brown (iron oxide); umber (iron oxide, manganese dioxide and clay sili-
     cates); burnt sienna;




                                                                                                    CONSERVATION SCIENCE IN CULTURAL HERITAGE
   – yellow ochers (iron oxide hydrate); raw sienna;
   – red ochers; rarely cinnabar, rarely minium;
   – green earth (iron silicate);
   – smalt (cobalt glass);
   – lapis lazuli (aluminum silicate containing sulfur).

   4.3. Substances extraneous to the frescoes

   Siliceous microparticles naturally present in dust.
   Black smoke with long-chain fatty acids.
   Gum resins of gum arabic type.
   Repainting pertaining to previous restorations.
   Animal proteins (glues) and linseed oil.

   4.4. Microbiological examination

   Study of the bacterial and fungal loads present on the frescoes made it evident that
the high level of bacterial load found in the restoration work performed without disinfec-
tion would have been drastically reduced, if concepts of asepsis had been adopted,
in other words, if the work had been conducted using disinfected materials, such as
sterilized natural sponges.8


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                                                                                                4.5. Evaluation of cleaning operation

                                                                                                  Determining surface colors through the use of numerical parameters obtained with
                                                                                              instrumental readings, addresses the need to document this representative character-
                                                                                              istic objectively and in a reproducible way, even after a long period of time has elapsed.
                                                                                              The colorimetric measurements were used to investigate whether the cleaning, with its
                                                                                              solvent, could in some way alter the chromatism of the fresco pigments.
                                                                                                  Instrumental readings were taken in ninety points corresponding to the colors, white,
                                                                                              yellow, pink, red, green, blue and the flesh tones. Pigment alteration was not found in
                                                                                              any of these points; instead there was an increase in brightness and a phenomenon
                                                                                              that was the reverse of yellowing. In all cases it was demonstrated how, by removing
                                                                                              the glue and carbon black from the paint, the cleaning had restored the brilliance and
                                                                                              tone of the colors.
G. Colalucci - Michelangelo Buonarroti: Restoration of the frescoes on the vaulted ceiling




                                                                                                4.6. Microclimatic study

                                                                                                 In anticipation of the end of the restoration, the General Staff of the Vatican Muse-
                                                                                              ums were careful to ensure the future of the newly restored frescoes. Since no “pro-
                                                                                              tective products” were used due to the fact their “life” is much shorter than that of the
                                                                                              natural surface of the frescoes, and being subject to alteration they must be removed,
                                                                                              consequently, attention focused on the optimal quality of the microclimate in the Sistine
                                                                                              Chapel, in addition to that of the cleaning and air supply.
                                                                                                 To design a system that met these requirements a study of the micro-climate inside
                                                                                              the Chapel had to be carried out. The task was given to Dario Camuffo and Adriana
                                                                                              Bernardi10.
                                                                                                 As a result of their study, Delchi Carrier designed and built a system that was able to
                                                                                              create a microclimate suited to the preservation of the frescoes, and at the same time
                                                                                              was acceptable for human comfort and well-being, so as to allow people to fully enjoy
                                                                                              their visit to the Sistine Chapel.11
                                                                                                 In 2014, the system was modernized and upgraded by Carrier, and the lighting in
                                                                                              the Chapel fully renovated with LEDs by Osram.12

                                                                                                4.7. Filming

                                                                                                 Unique in the history of restoration, was the cinematographic documentation of all
                                                                                              fourteen years of the cleaning operations. With these real-time records on film, it is
                                                                                              possible to re-examine the cleaning of any part or figure of Michelangelo’s frescoes.
                                                                                              The filming was carried out by the Japanese NTV crew from Tokyo. The seven thou-
                                                                                              sand meters of film are kept in the refrigerators of the photographic archives in the
                                                                                              Vatican Museums.13


                                                                                                5. Michelangelo’s painting

                                                                                                5.1. Color

                                                                                                 Thanks to the excellent technical execution and particularly resistant materials,
                                                                                              such as lime plaster and pozzolan, Michelangelo’s frescoes have withstood the test of
                                                                                              time and in spite of the previously described damage it was subjected to. The restora-


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tion therefore concentrated on the cleaning of the frescoes, allowing them to return to
their original state with the colors almost intact.
    Recovery of the unexpected colors immediately provoked great interest, making a
strong impact on the conscience of scholars and connoisseurs of Michelangelo’s paint-
ing, at the same time arousing unrestrained enthusiasm, but also some controversy.
The rediscovery of the color is certainly the most evident result of the cleaning of the
Sistine Chapel frescoes. There are, however, other less showy, less evident aspects of
these paintings, which come after a carefully studied examination.
    When the vault was dark and almost devoid of any color scheme, the composition
was based exclusively on the drawing and on the chiaroscuro effect created by the re-
painting of the false shadows. Today we find that Michelangelo has, however, entrust-
ed these effects mainly to three pictorial procedures, two of which are based on the
particular use of the brushstroke and the third on the calibrated juxtaposition of color.
Not merely chiaroscuro then, but color as volume. This is evident from the constant
consideration of interaction between light and color, an ancient medieval technique,
which he uses as an element of volumetric construction.
    But not all the color combinations depend on the effect produced by the interaction
between light and color, very often he combines and alternates different colors, just like
musical themes that contribute to the construction of the entire composition: the morel-
lone (reddish-violet color) of the Creator’s mantles, the green, the yellow, the red, the
skin tones of the nudes, the ocher of the bronze nudes, the white of the thrones and
the monochrome putti.
    Michelangelo’s palette, made of pigments of the highest quality and purity, is appar-
ently very rich, but is in reality based almost exclusively, as we have said, on colors
suited to fresco work which, as is known, essentially consist of a range limited to natural
or burnt oxides. The choice of color tones and combinations does vary however; in the
first half of the vault, Michelangelo’s colors are influenced by the culture and taste of
the late fifteenth century, as can be seen in the Erithraean Sibyl, the Delphic Sibyl and




                                                                                                    CONSERVATION SCIENCE IN CULTURAL HERITAGE
in the prophet Zechariah; in the second half of the vault he develops his own chromatic
sensitivity which will influence a great many artists whose work will later be known as
Mannerism. This is very evident in the tone of the mantles of God the Father in the
scenes of the creation, in the Persian Sybil, the Libyan Sibyl and the Prophet Jonah.

   5.2. The ductus of the brushstrokes

   In 1506, Pope Julius II commissioned Michelangelo to design and sculpt a large
tomb to be placed in the center of St. Peter’s Basilica in memory of his pontificate.
   At this point in time, the project is a very important one for Michelangelo and he will
devote his entire life to it. However, it soon becomes for him, what Condivi calls “the
tragedy of the tomb”, because a little later, due to economic reasons and political pru-
dence, the Pope curbs his enthusiasm and resolutely slows down the progress of the
project, causing great disappointment and a violent reaction in the Tuscan artist. For
this reason, when Julius II himself put pressure on Michelangelo to fresco the ceiling
of the Sistine Chapel, he received a proud refusal, justified by the fact he was not a
painter. Eventually though, Michelangelo gave in and after some initial hesitation about
the form of the composition, in 1508 he began the work that ended in 1512.
   Michelangelo said he was not a painter, but as a boy he had spent time in Florence
learning the art in the famous workshop of Ghirlandaio, the great fresco painter; the


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                                                                                              result is that in the Sistine, after a short trial period, he puts into practice a technique
                                                                                              of rare perfection.
                                                                                                  Leaving aside chisel and mallet, in taking hold of the paintbrush, he expresses him-
                                                                                              self in painting with the true language of this art composed of shape and color, but also
                                                                                              adds to its expressiveness, an almost imperceptible material structure, functional to the
                                                                                              image, that he obtains through a variety of brushstrokes and layers of color. His hand
                                                                                              moves from broad liquid strokes that are almost gestural to that dense network of fine
                                                                                              sharp brushstrokes and clean colors that create, as in Adam’s face, a slightly rough sur-
                                                                                              face that recalls the marble of the Brutus in the Bargello Museum in Florence sculpted
                                                                                              using a tooth chisel. And in the same scene of the creation of Adam, we pass from the
                                                                                              lightness of the hair and flowing beard to the strong stony face of God the Father. In
                                                                                              contrast, in the face of the Sibyl Eritrea, the brushstrokes are thickly amalgamated and
                                                                                              impalpable, just like the smooth gleaming surface of the wax-polished marble face of
G. Colalucci - Michelangelo Buonarroti: Restoration of the frescoes on the vaulted ceiling




                                                                                              the Virgin of the Pietà in St. Peter’s. In many cases, the different ways of representing
                                                                                              the hair is conceptually similar both in painting as in sculpture, just like the heavy clouds
                                                                                              on which rest the naked bodies of the Last Judgment that are similar to what Michelan-
                                                                                              gelo leaves of the block of marble from which he frees the bodies from their “prisons”.
                                                                                                  In parallel to the unfinished marble, there are some heads painted in the lunettes
                                                                                              and in the Last Judgment. In some there is a clear spatial function; in others, it is as if
                                                                                              the painter stopped as soon as the material started taking shape. Not a rough sketch
                                                                                              then, but a completed form which needed no additional detail, as in the figure on the
                                                                                              right in the Azor lunette.
                                                                                                  I would even venture to say that the vexed question of the ‘unfinished’ may even find
                                                                                              in the rereading of the frescoes a new key of interpretation.
                                                                                                  The parallel between Michelangelo the sculptor and Michelangelo the painter has
                                                                                              always been made, and it would seem superfluous to propose it again today, but there
                                                                                              is a difference now because, once upon a time the sculptor was identified in the little
                                                                                              attention he paid to color and the heavy use of chiaroscuro; today, on the other hand,
                                                                                              the sculptor is seen to compare painted surfaces and marble ones in a similar way.
                                                                                              Thus, volume, always taken into great consideration, is obtained through a combina-
                                                                                              tion of complementary colors and not the use of black shadows.
                                                                                                  Michelangelo’s painting derives from an extremely calibrated project, studied in
                                                                                              every part, in every detail, even in the choice of the various properties and workman-
                                                                                              ship of the plaster, according to the rendering of the color and surface appearance:
                                                                                              smooth, glazed or slightly rough.
                                                                                                  The previously mentioned ductus of the brushstrokes too, presents a wide range of
                                                                                              variants designed to achieve the expected spatial and volumetric effects of the com-
                                                                                              position.
                                                                                                  It is, therefore, pure reasoning combined with an extraordinary sense of art that
                                                                                              characterizes the work of Michelangelo. Hence, it would be wrong to look for the same
                                                                                              instinctive playful trait found for example, in Raphael or Titian, to name but two of his
                                                                                              contemporaries who, in their painting transfer the charming and attractive form and
                                                                                              chromatic scheme that belong to those who are born painters and are able to paint the
                                                                                              moment they hold a paintbrush in their hand.
                                                                                                  The Last Judgment, painted approximately twenty-five years after the vault, was
                                                                                              pictured as a scene in the empty space left by the breach in the altar wall; this is
                                                                                              demonstrated by the small figure to the right margin of the scene depicted with hands
                                                                                              resting on the real marble frame of the Chapel wall.


                                                                                        104
   The scene takes place in a space oriented toward the outside where the position of
the groups of figures respects the rules of perspective in the vanishing point. For this,
Michelangelo takes into account the optical effects related to the location of the single
figure in the space in relation to the greater or lesser distance of the image from the
eye of the observer and the volume of each figure.
   The concept of color in the Final judgment is based entirely on the blue sky. The
play of colors focuses on the contrast between the lapis lazuli background and the
modulated tones of the flesh color of the nude figures.
   The only hint of color is found in some drapery, where a more aggressive color
scheme can be observed, compared with that of the vault. The brushstrokes are also
more rapid and decisive, and rarely return to the ordered, almost mathematical struc-
ture seen in the vault.

   5.3. Three-dimensionality and spatiality

    As mentioned earlier, in Michelangelo’s complex painting there are several particular-
ly interesting practical expedients he has adopted to give the viewer the illusion of seeing
strongly evident three-dimensional figures positioned at various distances in space.
    Starting from the principle that the closer an object is to the eye, the more the de-
tails are perceived, Michelangelo painted the figures of the prophets, the sibyls and
the naked youths with sharp precision, using narrow blended brushstrokes and finely
detailed particulars so they appear close to the viewer, as these are found inside the
great hall. On the contrary: the figures in the central scenes with stories of the crea-
tion, which have to appear to be more distant, hovering beyond the physical space of
the vault, were painted with a textured weave of broad brushstrokes, so as to blur the
details of the faces and draperies.
    But the optical experiment that Michelangelo employs in the ceiling of the Sistine
goes further, because, especially in the large figures of the lunettes, he adjusts the




                                                                                                     CONSERVATION SCIENCE IN CULTURAL HERITAGE
“focus” of the image as in a photographic lens. Imagine that three focal planes pass
through the figure vertically, only one of which is depicted as if it were “in focus”. This
can be seen in the Jacob-Joseph lunette (Figure 9), where the forehead and the nose
on the face of old Jacob’s figure are in focus, but the hair, beard and chest are slightly
blurred and the details are lost .The knee, sharp and bright, is in focus. In this way, at
a distance of twenty meters one has the impression that Jacob’s forehead and knee
are on the same plane so that the figure does really appear to be curved and bent over
(Figure 9). The outline of the shoulder of the female figure in the Achim-Eliud lunette is
much sharper than that of the neck and shoulder of the figure of the child behind her in
order to push these parts farther into the background.
    Michelangelo adopts the same method for the Last Judgment, but with many varia-
tions some of them completely new as in the group of Christ the Judge and the Virgin,
where the face and the whole body of Christ are painted with a strength and sharpness
of detail suited to a figure that is at the center of the composition, while the Virgin, who
is near him but in the background, is painted in less detail and the face has a sort of
“vagueness” produced by fraying the lines using a jab of color given with the tip of a
paintbrush. But here Michelangelo has a stroke of genius, because he does not merely
paint using the tip of a paintbrush: he creates the complexion of the Virgin by juxtapos-
ing three separate colors, white, red, pink, anticipating by three centuries, divisionism
and pointillism (Figure 10).


                                                                                               105
G. Colalucci - Michelangelo Buonarroti: Restoration of the frescoes on the vaulted ceiling




                                                                                              Figure 9. The “Jacob and Joseph” lunette: it can be noted that the nose and eyebrows of Jacob’s
                                                                                              head in the forefront, are in focus, while the beard and hair are blurred, because they are in the
                                                                                              background.




                                                                                              Figure 10. “The Last Judgment”: In the “Virgin”, the textured weave effect of the brushstrokes
                                                                                              produced with jabs of the tip of the paintbrush are evident, as if anticipating pointillism far ahead
                                                                                              of its time.


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      Notes

1
   The restoration, which lasted from 10 June 1980 to 8 April 1994, was directed by Prof. Carlo
Pietrangeli, General Director of the Vatican Museums, by Dr. Fabrizio Mancinelli, Director of the
Byzantine, Medieval and Modern Art department; by Dr. h.c. Gianluigi Colalucci, chief restorer,
who also performed the work, and Dr. Nazzareno Gabrielli, Director of the Scientific Research
Bureau.
2
   Shearman, J., (1986) La costruzione della Cappella e la prima decorazione al tempo di Sisto
IV. In: La Cappella Sistina i primi restauri: La scoperta del colore. Novara: Istituto Geografico De
Agostini, pp. 22-35.
3
  Biagetti, B., (1936) La volta della Cappella Sistina: primo saggio di indagini sulla cronologia e la
tecnica della pittura di Michelangelo. Rendiconti della Pontificia Accademia Romana di Archeolo-
gia, Roma, vol. XII, pp. 199-220.
4
   Morresi, F., Gabrielli, N., (1999) Indagine sugli interventi censori. In: Michelangelo La Cappella
Sistina Documentazioni e Interpretazioni. Rapporto sul restauro del Giudizio Universale. Novara:
Musei Vaticani – Istituto Geografico De Agostini, vol. I, pp. 257- 278.
5
  Colalucci, G., (2015) Io e Michelangelo. Milano: Edizioni Musei Vaticani and 24 ore Cultura, pp.
31-32.
6
   The Vatican Museums have a laboratory for the restoration of paintings and a group of well-
prepared in-house restorers. The restoration itself was carried out by a limited number of restor-
ers for safety reasons. The restorers were: Gianluigi Colalucci (head), maestro Maurizio Rossi,
maestro Piergiorgio Bonetti, maestro John Grossi and restorer Bruno Baratti. Philip Petrignani
was in charge of computer graphics.
7
   Gabrielli, N., (1994) Introduzione. In: Michelangelo, La Cappella Sistina, documentazione e
interpretazioni- Rapporto sul restauro della volta. Novara: Istituto Geografico De Agostini, vol. II,
pp. 363-424.
8
   Montacutelli, R., Tarsitani, G., Maggi, O., Gabrielli, N., (1994) Indagini microbiologiche sugli
affreschi di Michelangelo in Cappella Sistina. In: Michelangelo, La Cappella Sistina, documenta-
zione e interpretazioni- Rapporto sul restauro della volta. Novara: Istituto Geografico De Agostini,
vol. III, pp. 297-299.
9
  Borrelli, E., Tabasso, M.L., (1994) Valutazione e documentazione dell’intervento di pulitura sugli




                                                                                                               CONSERVATION SCIENCE IN CULTURAL HERITAGE
affreschi di Michelangelo in Cappella Sistina. In: Michelangelo, La Cappella Sistina, documenta-
zione e interpretazioni- Rapporto sul restauro della volta. Novara: Istituto Geografico De Agostini,
vol. III, pp. 289-295.
10
    Camuffo, D., Bernardini, A., (1994) Il microclima della Cappella Sistina. In: Michelangelo, La
Cappella Sistina, documentazione e interpretazioni - Rapporto sul restauro della volta. Novara:
Istituto Geografico De Agostini, vol III, pp. 289-295.
11
   Grabon, M., (2015) Il nuovo impianto: lo studio e il progetto. In: La cappella Sistina venti anni
dopo, atti del convegno. Città del Vaticano: Edizioni Musei Vaticani.
12
    Bogani, C.M., (2015) Un sistema d’illuminazione digitale integrato. Lo studio e il progetto. In:
La cappella Sistina venti anni dopo, atti del convegno, Città del Vaticano: Edizioni Musei Vaticani.
13
   Maruyama, K., (2015) Il ruolo della Nippon Television. In: La cappella Sistina venti anni dopo,
atti del convegno, Città del Vaticano: Edizioni Musei Vaticani.



      References

[1]     Chastel, A., Shearman, J., O’Malleey, J., De Vecchi, P., Hirst, M., Mancinelli, F.,
        Colalucci, G., Bernabei, F., Gabrielli, N. (1986) La Cappella Sistina i primi res-
        tauri: La scoperta del colore. Novara: Istituto Geografico De Agostini.
[2]     Mancinelli, F., Colalucci, G., Gabrielli, N. (1994) Michelangelo, La Cappella Sis-
        tina, documentazione e interpretazioni- Rapporto sul restauro della volta, 3 vo-
        lumi. Novara: Istituto Geografico De Agostini.


                                                                                                         107
                                                                                              [3]     De Maio, R. (1990) Michelangelo e la Controriforma. Firenze: Sansoni Editore.
                                                                                              [4]     Mancinelli, F., Colalucci, G., Morresi, F., Gabrielli, N., Borrelli, E., Cerri, F., Gio-
                                                                                                      vannone, C., Laurenzi Tabasso, M., Falcucci, C., Sciuti, S., Montacutelli, R., Tar-
                                                                                                      sitani, G., Moggi, O., Fara, G.M., Chiari, G., Burragato, F., Ballirano, P., Maras,
                                                                                                      A. (1999) Michelangelo, La Cappella Sistina, documentazione e interpretazioni-
                                                                                                      Rapporto sul restauro del Giudizio Universale, 2 volumes. Novara: Musei Vati-
                                                                                                      cani - Istituto Geografico De Agostini.
                                                                                              [5]     Colalucci, G. (2015) Io e Michelangelo. Milano: Edizioni Musei Vaticani - 24 ore
                                                                                                      cultura.


                                                                                                    Biographical notes
G. Colalucci - Michelangelo Buonarroti: Restoration of the frescoes on the vaulted ceiling




                                                                                                 Gianluigi Colalucci was born in Rome in 1929. In 1953 he obtained his Diploma
                                                                                              from the Central Institute of Restoration with Cesare Brandi. In 1960 he joined the Lab-
                                                                                              oratory for the Restoration of Paintings of the Vatican Museums and in 1979 became
                                                                                              Chief Restorer. From 1980-1994 he was the technical manager and personally carried
                                                                                              out the restoration of Michelangelo’s frescoes in the vault and the Last Judgment, in
                                                                                              the Sistine Chapel.
                                                                                                 Since 2009 he has been engaged in the restoration of the fourteenth century fres-
                                                                                              coes by Buffalmacco in the Monumental Cemetery of Pisa. He has restored the works
                                                                                              of many artists including Michelangelo, Raphael, Titian, Giotto, Caravaggio, Manteg-
                                                                                              na, Crivelli, Lorenzo Lotto, Sartorio, Ferrazzi, Sciltian and Morandi. In 1990 and 1995,
                                                                                              respectively, the University of New York and the Universidad Politecnica de Valencia
                                                                                              conferred on him a Degree Honoris Causa. He has lectured throughout Europe, Ja-
                                                                                              pan, the United States, Canada, Cuba, Argentina, Brazil, Colombia and Australia.
                                                                                              In November 2015 he published “Io e Michelangelo”, also available in Spanish and
                                                                                              English.




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