Le diverse possibilità di valutazione di un’opera d’arte: il caso di studio della Mona Lisa
10.6092/issn.1973-9494/9990
Il tema dell'attribuzione e dell'autenticazione delle opere d'arte è ben noto ed è attualmente oggetto di accesi dibattiti. Ciò che deve essere sottolineato è l'importanza della terminologia utilizzata per distinguere i diversi gradi di certezza all'interno del sistema di attribuzione dell'opera d'arte e nel contesto delle diverse possibilità di valutazione di un'opera d'arte. È inoltre necessario integrare le competenze storico-umanistiche e tecnico-sperimentali che dovrebbero necessariamente condurre a una valutazione soggettiva e obiettiva al fine di arrivare a una verità scientifica univoca. Come caso emblematico, anche per l'unicità dell'opera, viene esaminata la Gioconda, prototipo del genio rinascimentale di Leonardo da Vinci. Allo stesso tempo, vengono anche studiate le versioni e le copie della Gioconda, basando l'esame su approfondite ricerche archivistiche e bibliografiche e tenendo conto dei risultati delle analisi storico-artistiche e tecnico-materiali da un punto di vista metodologico.
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Andrea Natali
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The Different Possibilities of Evaluating a Work of Art: Case Study of the Mona Lisa
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Andrea Natali
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The Different Possibilities of Evaluating a Work of Art: Case Study of the Mona Lisa
https://conservation-science.unibo.it/article/download/9990/10602
19
T    HE DIFFERENT POSSIBILITIES OF EVALUATING A
     WORK OF ART: CASE STUDY OF THE MONA LISA

    Salvatore Lorusso*1
    Foreign Member of the Russian Academy of Natural Sciences

    with the collaboration of Angela M. Braida and Andrea Natali




    Keywords: evaluating, work of art, Mona Lisa, research


    1. Introduction

   The purpose of this paper is to highlight the importance of several aspects which are
to be considered fundamental in correctly arriving at a final judgement in evaluating a
work of art [1-10].
   They are:
   • respect for the “history” that accompanies the art object;
   • correctness of the terminology which, as such, implies concepts and meanings to
be observed and followed;
   • the methodological path to be used to provide the answer to the specific question
that has been put forward, necessarily involving the synergy of different scientific com-
petences with respect to the holistic value of the cultural artefact.
   As regards the much debated subject of attribution and authentication of art works,
the following points are discussed:
   a) the different evaluations that can be given to a work of art to distinguish the dif-
ferent degrees of certainty in attribution;
   b) the corresponding and complete methodological process of evaluation;
   c) the case study that refers to Leonardo da Vinci’s work, considered to be one of
the most prestigious of all time: the “Mona Lisa – Gioconda”, a unique piece in the
art world;
   d) a summary of Leonardo’s art that includes the various versions and copies of his
works as reported in archival-bibliographic sources;
   e) the synthetic outline of the historical and diagnostic-analytical investigation of
the oil painting on canvas, the St. Petersburg “Mona Lisa with columns” conducted
in order to obtain the correct attribution, as an emblematic example of what has been
highlighted above.

*   Corresponding author: salvatore.lorusso@unibo.it
                                                                                                   These topics are discussed in the historical-technical Journal “Conservation Sci-
                                                                                                ence in Cultural Heritage” in connection with the fundamental importance of interdis-
                                                                                                ciplinarity (7-8, 10).


                                                                                                   2. The attribution and authentication of art work

                                                                                                    A work of art is characterized by a set of values: cultural, historical, aesthetic,
                                                                                                artistic, spiritual, symbolic, social, technical, economic, financial, mercantile which
                                                                                                also include aspects of merchandising, authenticity, identity, interdisciplinarity and
                                                                                                internationalization. These in turn concern different areas of investigation: histor-
                                                                                                ical-humanistic, philological-philosophical-social, technical-economic-managerial,
                                                                                                legal-identitary.
S. Lorusso, A.M. Braida, A. Natali - The different possibilities of evaluating a work of art




                                                                                                    There is no doubt, therefore, that in dealing with the numerous and complex prob-
                                                                                                lems in the sector of cultural and environmental assets, there is a need for contribu-
                                                                                                tions deriving from different scientific experiences and the involvement of different
                                                                                                skills, without leaving aside aspects relating to the employment market where the
                                                                                                demand is for more a more practical experience and more transversal and entrepre-
                                                                                                neurial skills.
                                                                                                    The above highlights the importance of interdisciplinarity in the protection and en-
                                                                                                hancement of cultural heritage and is especially true when dealing with the attribution
                                                                                                of art works.
                                                                                                    In the specific case of art work attribution, the consequent holistic value of the cul-
                                                                                                tural asset is based on the sum value of the individual values; a correct attribution
                                                                                                and authentication should therefore establish the corresponding economic-financial-
                                                                                                mercantile-market value and ultimately, its price [11].
                                                                                                    As regards the reproduction of art, Figure 1 shows the terminology used in the
                                                                                                field to distinguish between the different degrees of certainty in the attribution of a
                                                                                                work of art [12].




                                                                                                Figure 1. Terminology used in the field to distinguish between the different degrees of certainty in
                                                                                                the attribution of a work of art.



                                                                                          308
    In the art market and world of auction houses, the evaluation carried out by an
expert is a subjective evaluation, based on an analysis of the historical, stylistic,
aesthetic, iconographic aspects and is a visual evaluation of the artefact comple-
mented by the recognized competence of an evaluator. The art expert, therefore,
with his personal critical judgment and, on the basis of evaluative comparisons
between the artistic qualities of the work in question and his hypothetical “au-
thentic”, decrees whether it is authentic or not, providing his expertise and thus
determining the price.
    A problem deriving from this result, in the context of this evaluation, is that a
prejudice can intervene on the part of the expert, who may be influenced by other
considerations such as defending their reputation, financial questions and com-
petence.
    Art objects are examined by the experts of the auction houses and their opinions
expressed and summarized in a Condition Report containing qualitative but not quan-
titative information.
    It is evident then that the current problem concerning fakes and, in general, non-
authentic works, is precisely that of ascertaining the authenticity or non-authenticity
of a work by means of scientific methods, i.e. the use of appropriate diagnostic and
analytical technologies which will result in an objective evaluation.


   3. A
       methodological path towards obtaining a subjective and objective evalu-
      ation for the attribution and authentication of an art work

    The methodological path includes the following procedural steps [2,11]:
    a) A historical anamnesis of the work
    The work of art, for which a correctly completed report is written, includes evalu-
ative elements such as the author, period, artistic style, iconography and technical




                                                                                                   CONSERVATION SCIENCE IN CULTURAL HERITAGE
execution.
    b) A technical-material-conservative analysis
    This will include a description of the morphological elements regarding the sur-
face and stratigraphy, characterization of the materials, the state of conserva-
tion (pathologies present, level of degradation, etc.).It should be borne in mind,
however, that in investigating the composition of the materials, as stated above,
it is important to ascertain their provenance by comparing the data obtained from
the analysis of the materials of the work in question and the data obtained from
bibliographic sources.
    On the one hand, for the “copy” and / or “fake” and / or any of the other categories,
the historical-artistic subjective evaluation completed by the diagnostic-analytical ob-
jective evaluation provides a unique answer regarding the degree of certainty of the
attribution. On the other, for the artefact that has been “reproduced” or realized using
computer technology, there is no possibility of providing an answer, since it is now
possible to produce a work that is identical to the “original” / “authentic” work in form,
color and even “materiality”.
    However, this means ascertaining the conceptual and applicative limits that exist
in “art ethics and aesthetics”, in the hope that the resulting data and information are
in accord.



                                                                                             309
                                                                                                   4. Various versions and copies of the Mona Lisa

                                                                                                    It is well known that attributions can be revised over the years and that the fre-
                                                                                                quent heated debates between experts should in fact openly and synergistically
                                                                                                lead to a valid scientific discussion. This is based on a system of attribution and
                                                                                                authentication that has to balance the initial subjective evaluation, of unquestiona-
                                                                                                ble importance, with an equally indisputable objective evaluation which definitively
                                                                                                confirms the scientific truth.
                                                                                                    Here, then, is how one should proceed in relation to evaluating the versions and
                                                                                                copies of the Mona Lisa: an emblematic case also due to the uniqueness of the work,
                                                                                                a prototype of the Renaissance genius of Leonardo da Vinci.
                                                                                                    A number of Leonardesque versions and numerous copies by pupils and / or follow-
                                                                                                ers and / or authors referring to the same subject of the Mona Lisa exist. Therefore, to
S. Lorusso, A.M. Braida, A. Natali - The different possibilities of evaluating a work of art




                                                                                                reach a correct opinion, an accurate archival-bibliographic research was carried out in
                                                                                                2015, based on the intense bibliographic material available, which was complemented
                                                                                                not only by historical but also technical data. The findings relating to the corresponding
                                                                                                subjective and objective evaluation of these works are not only the result of stylistic
                                                                                                and aesthetic analyses, but also technical-material ones, obtained using reliable in-
                                                                                                novative diagnostic-analytical technologies and carried out by several laboratories1.
                                                                                                    The research led to selecting a number of the best works. However, before exam-
                                                                                                ining them and the relative hypotheses regarding attribution, a necessary distinction
                                                                                                must be made.
                                                                                                    Whether the art works are versions or copies attributable to Leonardo and subject
                                                                                                to different evaluation by the experts, it should be noted that the expression “by Leon-
                                                                                                ardo” refers to the fact that experts unanimously agree in their judgement on works ref-
                                                                                                erable to Leonardo. On the other hand, the expression “attributed to Leonardo” refers
                                                                                                to the non-unanimity of the experts in their judgement. This distinction is evidently valid
                                                                                                for any author whose work is to be evaluated where there is a corresponding problem
                                                                                                of attribution.
                                                                                                    After an archival-bibliographical research the paintings selected were:
                                                                                                    • the Louvre Mona Lisa, an oil painting on wood completed in 1517 bearing traces
                                                                                                of columns on either side of the picture. For this work the experts’ judgement is unani-
                                                                                                mous, in particular, for some specific parts: the face, the hands, the embroidery.
                                                                                                    • It has, however, given rise to another problem relating to the following interpretations:
                                                                                                    • that the painting initially had columns which were later trimmed to make it fit into
                                                                                                a smaller space;
                                                                                                    • that the painting had no columns and the traces present at the edge could have been
                                                                                                added by a restorer taking into consideration another version: the Isleworth Mona Lisa.
                                                                                                    • the Prado Mona Lisa, an oil painting on wood, executed at the beginning of the
                                                                                                16th century at the same time as the Mona Lisa at the Louvre, set in a Milanese con-
                                                                                                text and stylistically close to the work of Leonardo’s pupils, Salai and Melzi;
                                                                                                    • the Reynolds Mona Lisa, an oil painting on wood, the best of the selected works
                                                                                                due to its high quality. It was painted at the beginning of the 17th century in Fontaine-
                                                                                                bleu by a French court artist or a visiting artist;
                                                                                                    • the Isleworth Mona Lisa, an oil painting on canvas, portraying a young Mona Lisa
                                                                                                with columns and clearly unfinished.
                                                                                                    As regards the attribution of the Isleworth Mona Lisa to Leonardo, the Mona Lisa
                                                                                                Foundation has retraced the historical events that have accompanied the painting


                                                                                          310
across the years. It reports how in 1922 the painting underwent an initial evaluation by
experts who, on the basis of a thorough stylistic and aesthetic analysis, unanimously
agreed that the Isleworth Mona Lisa, i.e. the “Earlier Mona Lisa”, was a “version by
Leonardo”, even though some details differed from the Louvre version.
    This group of experts had examined the Louvre Mona Lisa at an earlier date in 1913
and therefore already had a good understanding of Leonardo’s artistic technique.
    The group was composed of 9 experts:
    − Prof. Commendatore Lorenzo Cecconi, Curator of the Academy of San Luca
    − Dr. Arduino Colasanti, Former Director-General of Antiquities and Fine Arts
    − Dr. Giulio Cantalamessa, Chief Director of the Borghese Gallery in Rome
    − Count San Martino di Valperga (Piedmont), for many years Honorary President
of the Art
    − Institutes of Italy, and President of the 1911 Exhibition
    − Commendatore Marini, Inspector General and Director-General of the Beaux Arts
    − Prof. Anto Sciortino, Director of the British Academy of Arts in Rome
    − Prof. Adolfo Venturi, well-known art critic and author
    − Mr. Ludovico Spiridon, one of the most prominent art collectors in Italy of his day,
and owner
    − of the famous “Leda Spiridon” version attributed to Leonardo, now in the Uffizi
    − Mr. Cesare Segre, well-known collector.
    Our archival-bibliographical research [14-15], as previously stated, has examined
from a methodological point of view – a point that cannot be emphasised too much
– the findings of both the historical-artistic and technical-material analyses. This meth-
odology led to highlighting the distinction between the two “versions” by Leonardo, in
other words the Louvre and Isleworth Mona Lisas and their “copies”, the Prado and
Reynolds Mona Lisas. In particular, the two authentic versions by Leonardo are from
two different periods: the Isleworth depicts a figure from an earlier period (about 11 –
12 years) compared to the Louvre Mona Lisa, which reveals a more refined technique,




                                                                                                   CONSERVATION SCIENCE IN CULTURAL HERITAGE
and is spatially and geometrically of different dimensions.
    Consequently, it can be assumed that, in addition to the Prado and Reynolds Mona
Lisas, all other successive Mona Lisas are actually copies of one or the other authentic
versions, or a combination of both.


  5. Considerations on the Isleworth Mona Lisa (the Earlier Mona Lisa)

   In reference to the Louvre Mona Lisa and the Isleworth Mona Lisa, though depicting
two separate portraits of the same woman, it is appropriate to highlight an aspect that
however links both: the Leonardesque meaning of beauty. Leonardo’s oldest portrait
of a lady is “Portrait of Ginevra de’ Benci” which, on the reverse, bears the motto: “Vir-
tutem forma decorat” (beauty adorns virtue).
   It follows that virtue pre-exists and is then adorned by beauty. In the early 1500s,
therefore, what had to emerge from a woman’s portrait was not only beauty, but also
morality, nobility, chastity, a fear of God, religiosity and, more rarely, culture.
   This is what Leonardo is believed to have wanted to portray.
   In particular, the following considerations related to the authentication of the Isle-
worth Mona Lisa (Earlier Mona Lisa) as being another version by Leonardo are re-
lated to:


                                                                                             311
                                                                                                    1. The statements made by Vasari in 1550 and 1568 in which he points out that
                                                                                                Leonardo had left the painting of the “Lady on the balcony” unfinished, and that the
                                                                                                same painting was finished in 1517. The Louvre version had already been completed
                                                                                                in 1517 (for Carlo Pedretti and Pietro Marani 1513).
                                                                                                    2. Further evidence of the possible existence of another version of the portrait is
                                                                                                a pen and ink sketch by Raphael (Raffaello Sanzio). It depicts a young woman on a
                                                                                                balcony with columns dating back to around 1504 and drawn while he was in Florence
                                                                                                to observe Leonardo’s work. As the compositional elements are unique and do not
                                                                                                appear in any other painting, this Mona Lisa must have been near completion when
                                                                                                Raphael saw it in 1504.
                                                                                                    3. The stylistic and aesthetic analysis and the artistic technique confirm the figure is
                                                                                                a younger one and is evident in:
                                                                                                    a. the thinner hands and slimmer fingers and, in particular, the more relaxed fore-
S. Lorusso, A.M. Braida, A. Natali - The different possibilities of evaluating a work of art




                                                                                                finger of the right hand;
                                                                                                    b. the response to the predominant feature of Leonardo’s portraiture, in other words,
                                                                                                the contrast between the warmer tones of the hands and the paler complexion of the
                                                                                                face and chest;
                                                                                                    c. Leonardo’s interest in geometry which is clearly shown by the “Golden Ratio”; this
                                                                                                is connected to Leonardo’s studies on “divine proportion”, an integral part of many of
                                                                                                his works, in particular on the human body2. At times indeed, he seems obsessed by
                                                                                                this aspect: his work on the Isleworth Mona Lisa, for example, is commented on by Frà
                                                                                                Pietro da Novellara (ambassador of Isabelle d’Este, an important Renaissance figure).
                                                                                                He reports that Leonardo was intensely focused on the geometry which was further ac-
                                                                                                centuated by the effect given by the glazing, a technique he had perfected after 1508;
                                                                                                    d. the important relationship between mathematics and art that exists in Leonardo’s
                                                                                                work should not be underestimated; its importance is well-documented in numerous
                                                                                                letters, papers and notes.
                                                                                                    4. The innovative investigative technique on what was not visible and revealed that
                                                                                                both the Louvre and Isleworth portraits were painted by the same author; this is in
                                                                                                reference to the oil painting technique of using successive layers of glazing which
                                                                                                produced transparent veils of colour and shading defined ‘sfumato’.
                                                                                                    Professor John Asmus of California University and Professor Vadim Parfenov of
                                                                                                St. Petersburg Elettrotechnical University [13] have recently applied their well-prov-
                                                                                                en method on various copies of the Mona Lisa, including the two Mona Lisa paintings
                                                                                                of the Louvre and Isleworth. The method measures the brushstrokes related to the
                                                                                                “sfumato” and the “chiaroscuro” of the faces by analyzing the distribution of billions
                                                                                                of pixels of the histograms obtained by multispectral digitization. In this regard, the
                                                                                                measurements were directed in particular to the mouth, nose and eyes, as they rep-
                                                                                                resent distinctive areas on which artists preferentially use their brushstrokes. They
                                                                                                have therefore been defined as “fingerprints”. In the case of the various copies each
                                                                                                was distinctly different from another. The exception related to the faces of the Mona
                                                                                                Lisa of the Louvre and Isleworth for which Prof. Asmus stated that there is a 99%
                                                                                                certainty that these two paintings were executed by the same author.
                                                                                                    In this regard, it is also possible to provide a quantitative value for the “sfumato” by
                                                                                                instrumentally determining the trichromatic coordinates of the differences in colour of
                                                                                                the colored surfaces using a spectrophotometric colorimeter, bearing in mind a chro-
                                                                                                maticity diagram, in other words: L = brightness (which decreases from the brightest to
                                                                                                the darkest portions), h = hue, C * = saturation [15].


                                                                                          312
    This is something intangible in Leonardo’s works and the main reason why it is so
difficult to copy his paintings.
    5. In January 2011, a French engineer, Pascal Cotte, examined the painting using
a non-invasive multispectral technique, Layer Amplification Method (LAM), which re-
vealed some preparatory drawings underlying the pictorial film and thus evidencing it
is not a direct copy.
    6. Another investigative method developed by Joe Mullins in 2012 for the “Regres-
sion Project”, involved the application of a particular forensic technique to art. The
technique confirmed that the portraits of the Louvre and Isleworth Mona Lisas are
of the same woman at different ages, the Isleworth being approximately 11-12 years
younger than the Louvre Mona Lisa, dating it to about 1505-06 (this is the year calcu-
lated after subtracting the 11 years difference from the year the Louvre Mona Lisa was
completed in 1517).
    7. The support material, hand-woven linen or Reims canvas has the same charac-
teristics as the support used by Leonardo to paint his famous draperies in the context
of his 1470 studies.
    8. The analytical investigations have ascertained the techniques used in the prepa-
ration of the aforementioned canvas support on which a thin layer of hard gypsum was
applied, including the applications for the painting, the priming and the colour; they
have also identified the complete range of pigments and other media used, highlighting
their availability and use since the beginning of the 16th century.
    9. Ultimately, Leonardo’s palette, the manner and sequence with which he mixed
and applied colours closely follow the meticulous instructions he himself wrote in his
“Treatise” in the section devoted to painting. It is evident that Leonardo’s palette for the
Isleworth Mona Lisa remains faithful to his indications and theories and, in this regard,
definitive proof is in the presence of the earth pigments, umbers, Siennas
    (Fe 2 O3 al 40% + Mn O2 al 15% + Si + Al2 O3 ) which were used by Leonardo in some
of his most important works.




                                                                                                     CONSERVATION SCIENCE IN CULTURAL HERITAGE
   6. O
       n the attribution of the oil painting on canvas: the St. Petersburg “Mona
      Lisa with columns”

    The methodological path followed to reach a final answer regarding attribution was
applied to an oil painting on canvas “Mona Lisa with columns” from a private collection
(Figure 2).
    The examination was aimed at identifying the constituent materials and character-
izing the pictorial technique. Its purpose was to identify its execution artistically and
provide a reliable answer based on a subjective and objective evaluation.
    The study was conducted with the help of a chemist, art historian and restorer as
well as a physicist and technician-diagnostician, working together and integrating their
skills to lead to one final result.
    The historical and diagnostic-analytical investigations were carried out, partly in
St. Petersburg in the Museum where the painting was located and, in part, on sam-
ples taken from the artefact, in the Diagnostic Laboratory for Cultural Heritage of the
University of Bologna (Italy) with the use of portable and non-portable equipment,
responding to principles of innovation and reliability and according to the correct
methodological path


                                                                                               313
S. Lorusso, A.M. Braida, A. Natali - The different possibilities of evaluating a work of art




                                                                                                          Figure 2. Oil painting on canvas, St. Petersburg “Mona Lisa with columns”



                                                                                                    that must distinguish the complete intervention. Following the investigations and the
                                                                                                corresponding findings, some considerations were made on the work in question and
                                                                                                a comparison made with Leonardo’s “Mona Lisa” exhibited at the Louvre in Paris. A
                                                                                                summary of the results is given below.
                                                                                                    • In the case of the St. Petersburg Mona Lisa with columns, the support is a linen
                                                                                                canvas with a coarse irregular texture, its size being compatible with the “standard”
                                                                                                one that was commonly found from the first half of the 1600s in the Flemish region. The
                                                                                                Louvre Mona Lisa is instead on wood.
                                                                                                    • The materials used for the preparation, in the case of the St. Petersburg Mona
                                                                                                Lisa with columns, can be traced to a German-Flemish practice used between 1620-
                                                                                                1680 in a Parisian context. Leonardo, on the contrary, used a preparatory layer made
                                                                                                of plaster.
                                                                                                    • The colored primer found in the St. Petersburg Mona Lisa with columns was used
                                                                                                starting from the second half of the 1500s.
                                                                                                    • The dating of the canvas support of the St. Petersburg Mona Lisa with columns
                                                                                                to between 1520-1660 and therefore excludes the period of life and work of Leonardo
                                                                                                (1452-1519).
                                                                                                    It was possible to conclude that the painting of the St. Petersburg “Mona Lisa with
                                                                                                columns” represents a copy of the work “Mona Lisa” by Leonardo, referable to a period
                                                                                                between 1590 and 1660. However, it is important to highlight the good workmanship,
                                                                                                its readability and the expressiveness that emanates from the work, albeit with inad-
                                                                                                equate brushstrokes and devoid of the thickness in the colours Leonardo typically

                                                                                          314
used in his landscapes, particularly with regard to the rendering of the background in
general, which is of a modest design.
    Its execution is, ultimately, of Nordic derivation, specifically German-Flemish, and is
influenced by the French school [15].

    7. Conclusion

   He was a genius but had no knowledge of Latin.
   It is well known that Leonardo polemically and proudly defined himself as a homo
sanza lettere i.e. as having no regular school education and no knowledge of Latin,
which was taught to those who undertook a profession in law or medicine and which,
at that time, was indispensable to read the classics. For the rest of his life, Leonardo
claimed this condition of illiteracy, contrasting the wisdom of the learned with the value
of direct sperientia, i.e. the ability to investigate nature guided solely by observation.
   It is equally true that today, the complete reconstruction of his personal library, cre-
ated for the first time by an international group of specialists, proves these claims to be
false. In fact, he was not educated in the use of Latin, but self-taught himself over the
years with the aid of grammar books and dictionaries.
   This makes of Leonardo an emblematic example of humility and genius and, as
such, a reference for experts whether they be historians or technicians dealing with the
process of evaluating, attributing and authenticating a work of art.
   This finally brings us back to the title of the editorial in this issue of the Journal: “The
integration of knowledge of the mind, heart and hands in science and life”.


    Notes

1
       This refers to the sequence of investigations on the Mona Lisa in the Louvre carried out




                                                                                                           CONSERVATION SCIENCE IN CULTURAL HERITAGE
       in 2004 by the “Research and Restoration Center of the Museums of France” included in
       the studies collected in the compendium “Au coeur de La Joconde – Leonardo da Vinci
       décodé”. The investigations were examined together with those indicated by the National
       Gallery in London, thus allowing a comparison to be made with other works by Leonardo;
       it also includes the analytical research conducted by Hermann Kuhn and Maurizio Seracini
       on samples taken from the Isleworth Mona Lisa, as reported in the publication by the Mona
       Lisa Foundation “Leonardo da Vinci’s Earlier Mona Lisa” [13].
2
       These studies indicate that the human body constitutes the most aesthetically beautiful
       relationship between the different parts, such as the trunk and legs. The pencil drawing of
       the Vitruvian Man by Leonardo, is an excellent example.



    References

[1].   Lorusso S., Matteucci C., Natali A. (2006). Sulla attribuzione e sullo stato di conser-
       vazione di tre dipinti: anamnesi, confronto, valutazione. In: Lo stato dell’arte. Siena,
       28-30 Settembre. Florence: Nardini. (vol., pp. 679 – 688) ISBN 88 404 41 50 6.
[2].   Lorusso S., Matteucci C., Natali A. (2007). Anamnesi storica, indagini analitico-
       diagnostiche e monitoraggio ambientale: alcuni casi di studio nel settore dei beni
       culturali, Pitagora Editrice, Bologna.


                                                                                                     315
                                                                                                [3].    Lorusso S., Matteucci C., Natali A., Visco V. (2007) Diagnosis and digitization of
                                                                                                        Dantesque Code “Phillipps 9589”. Quaderni di Scienza della Conservazione. vol.
                                                                                                        7; Pitagora Editrice, Bologna.
                                                                                                [4].    Lorusso S., Natali A., Apicella S.A., Livigni V., Scandagliato D. (2013). Conside-
                                                                                                        razioni storico-artistiche sull’attribuzione del dipinto San Francesco Stimmatizza-
                                                                                                        to a Tiziano Vecellio, Il giornale delle prove non distruttive monitoraggio diagno-
                                                                                                        stica (Organo ufficiale dell’AIPnD), anno XXXIV, N. 3 – Settembre 2013
                                                                                                [5].    Lorusso S., Matteucci C., Natali A., Apicella S., (2013) Traditional and non-tra-
                                                                                                        ditional. innovative and ephemeral materials and techniques in today’s cultural
                                                                                                        heritage, Russian Chemical Bulletin. International Edition, Vol. 62, No. 7, pp.
                                                                                                        1671-1681, July 2013 ISSN: 1066-5285 (Print) 1573-9171 (Online)
                                                                                                [6].    Lorusso S., Natali A., Palla F. (2015) Risk Management in the Cultural Heritage
                                                                                                        Sector: Museums, Libraries, Archives, Mimesis Edizioni, Milano-Udine
S. Lorusso, A.M. Braida, A. Natali - The different possibilities of evaluating a work of art




                                                                                                [7].    Lorusso S., Barone V., Colizzi L., Fonseca C.D. (2014) Analytical-diagnostic and
                                                                                                        computing technologies for the attribution, authentication and economic evalu-
                                                                                                        ation of art works, Conservation Science in Cultural Heritage. vol. 14. Mimesis
                                                                                                        Edizioni, Milano-Udine
                                                                                                [8].    Lorusso S. (2014) Critical Heritage in Cross-Cultural Perspectives. Interdisci-
                                                                                                        plinarity, Internationalization and Social Media in Cultural Heritage: Some Case
                                                                                                        Studies, Conservation Science in Cultural Heritage. vol. 14. Mimesis Edizioni,
                                                                                                        Milano-Udine
                                                                                                [9].    Lorusso S., Matteucci C., Natali A., Pentrella R., Lopardi A. (2008). Indagini chi-
                                                                                                        mico-fisiche e diagnostiche sugli apparati decorativi di Palazzo Rivera a L’Aquila.
                                                                                                        Materiali e strutture, vol. 9-10; p. 108-128., ISSN: 1121-2373
                                                                                                [10].   Lorusso S., Matteucci C., Natali A. (2011) The Shroud of Turin between history
                                                                                                        and science: an ongoing debate, Conservation Science in Cultural Heritage. vol.
                                                                                                        11. Mimesis Edizioni, Milano-Udine
                                                                                                [11].   Lorusso S., Matteucci C., Natali A. (2010) Il mercato dell’arte e le case d’asta:
                                                                                                        valutazione diagnostico-analitica e economico-finanziaria. L’autentico, il falso,
                                                                                                        il riprodotto nel settore dei beni culturali. Bologna, Pitagora Editrice. p. 1-208,
                                                                                                        ISBN:88-371-1797-3
                                                                                                [12].   Lorusso S., Natali A. (2014), Le diverse tipologie di riproduzione nell’arte, in “Il
                                                                                                        diritto dell’arte. La protezione del patrimonio artistico” a cura di Negri-Clementi
                                                                                                        G., Stabile S., Skira, Ginevra-Milano, pp.155-167, ISBN 978-88-572-2627-9
                                                                                                [13].   The Mona Lisa Foundation (2018) Leonardo da Vinci’s Earlier Mona Lisa, 5th
                                                                                                        Edition, August 2018, The Mona Lisa Foundation, Zurich, Switzerland.
                                                                                                [14].   Lorusso S., Natali A. (2015) Mona Lisa: A Comparative Evaluation of the Differ-
                                                                                                        ent Versions and Their Copies. Conservation Science in Cultural Heritage. vol.
                                                                                                        15, pp. 57-109 ISBN: 978-88-5753-547-0. Mimesis Edizioni, Milano-Udine
                                                                                                [15].   Lorusso S., Matteucci C., Natali A., Apicella S., Fiorillo F.L. (2013) Diagnostic-
                                                                                                        analytical study of the painting “Gioconda with columns” Conservation Science
                                                                                                        in Cultural Heritage. vol. 13, pp. 75-127 ISSN: 1974-4951. Mimesis Edizioni,
                                                                                                        Milano-Udine.




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  Biographical notes

    Salvatore Lorusso is a former full Professor of the University of Bologna. He is
Foreign Member of the Russian Academy of Natural Sciences; Emeritus Professor of
the Cultural Heritage Institute of Zhejiang University, China; former Visiting Professor
of the Academy of Social Science of Zhejiang University, China; Visiting Professor of
the Faculty of Arts, Lomonosov Moscow State University, Russia; former Vice-president
and now, a Councilor of the Società Italiana per il Progresso delle Scienze (SIPS-estab-
lished in 1839). Direttore Generale of the Accademia della Cultura Enogastronomica.
His biography appears in the 2016 Marquis Edition of Who’s Who in the World. He is
the founder and director of two book series relating to the specific issues pertaining to
the sector of cultural and environmental heritage. He is the author of over 430 publica-
tions in national and international journals and of 22 volumes and monographs cover-
ing commodity science, cultural heritage and environment. In 1997, he founded the
Diagnostic Laboratory for Cultural Heritage at the Ravenna Campus of the University of
Bologna and remained head of the Laboratory for eighteen years. In 2001, he founded,
and is Editor-in-Chief of, the historical-technical Journal “Conservation Science in Cul-
tural Heritage”. His scientific work deals mainly with the study of the “system-artifact-
environment-biota” and diagnostic, analytical, technical and economic evaluation within
the context of the protection and valorization of cultural and environmental heritage.


   Summary
   The topic of attribution and authentication of works of art is a well known one, and is
currently the subject of heated debate. What must be highlighted is the importance of
the terminology used to distinguish the different degrees of certainty within the system
of art work attribution, and in the context of the different possibilities of evaluating a
work of art. It is also necessary to integrate historical-humanistic and technical-experi-




                                                                                                   CONSERVATION SCIENCE IN CULTURAL HERITAGE
mental skills which should necessarily lead to a subjective and objective evaluation in
order to arrive at a univocal scientific truth.
   As an emblematic case, also owing to the uniqueness of the work, the Mona Lisa,
prototype of the Renaissance genius of Leonardo da Vinci, is examined.
   At the same time, the versions and copies of the Mona Lisa are also studied, bas-
ing the examination on in-depth archival and bibliographic research, and taking into
account the findings of the historical-artistic and technical-material analyses from a
methodological point of view.
   The findings have highlighted the distinction between the two authentic versions
by Leonardo, i.e. the Louvre Mona Lisa and the Isleworth Mona Lisa (or Earlier Mona
Lisa) and the two copies, i.e. the Prado and Reynolds Mona Lisas. The latter two, con-
sidered to be the most complete and qualitatively better than many others, are in fact
either copies of previous Mona Lisas or of the two authentic versions. Finally, from an
experimental perspective, in order to provide an answer regarding attribution, a pre-
cise methodological approach was applied to the painting on canvas “Mona Lisa with
columns” (St. Petersburg), establishing that it was a copy, albeit a well-executed one.




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