Scientific Analysis on Leonardo da Vinci's "Adorazione dei Magi"

The Leonardo da Vinci's "Adorazione dei Magi" after the restoration, during the press conference of  23 September 2014.

(© Opificio delle Pietre Dure – Foto di Pino Zicarelli)

Today we will talk about one of the greatest unfinished masterpieces by Leonardo da Vinci: the well-known "Adoration of the Magi", a painting in oil and oily tempera realized on planks of poplar wood, with a square shape (about 2.50 meters per side). 

The painting, partially realized between 1481 and 1482, portrays an iconographic theme widespread in Florentine art and much requested by the clients during the period between 1400 and 1500: this is confirmed by several contemporary works such as the "Adorazione dei Magi" by Lorenzo Monaco (1422), Gentile da Fabriano (1423), Masaccio (1426), Botticelli (1475), Filippo Lippi (1469) and so on. 

The work, commissioned in 1481 by the monks of San Donato in Scopeto to the great Florentine artist, has come to us in the guise of a great preparatory monochromatic drawing, more or less accurate in its different scenes, which allowed scholars to better understand the painting technique of Leonardo. 

From November 2011 until March 2017, an intense and fruitful diagnostic and restoration campaign was conducted upon the Leonardo's art piece, moved for the occasion from the “Galleria degli Uffizi” to the laboratories of the “Opificio delle Pietre Dure” in Florence and, more precisely, in its headquarters at the “Fortezza da Basso”. Many diagnostic tests were performed on the painting: in fact, in addition to the complete high-resolution photographic documentation both in the visible and ultraviolet region, multi-NIR reflectography and colorimetric measurements, chemical and spectrophotometric investigations, X-rays and XRF scanning, optical coherence tomography (OCT) have been conducted, together with 3D scanning and three-dimensional surveys for the measurement of micro-deformations. This wide diagnostic campaign hasn’t been the only investigation applied to the famous Leonardo's art piece, but it appears to be the most complete, recent and well documented one. 

Considering the achieved results, also compared with other informations derived from diagnostic tests performed on different paintings of the same artist, such as the "Vergine delle Rocce" housed in the National Gallery of London, the "Sant’Anna, la Vergine e il Bambino con l’agnellino" of the Louvre Museum and the unfinished "San Girolamo" of the Vatican Museums, it was noticed that Leonardo’s painting technique, during his artistic life time, remains almost unchanged. The artist was used to make a rough freehand drawing (as in the case of "Adorazione dei Magi") or with the aid of a cardboard and, then, he completed it by means of overlaid layers of color that, finally, conferred to the painting the characteristic nuanced Leonardo's contours, more or less accentuated according to the needs of perspective. It is also common to appreciate his use of the “nail and rope” technique for tracing lines: these helped him to create architectural structures and to arrange in perspective the characters and the elements of the painting: in the "Adorazione dei Magi", we can even see the hole left by the nail placed by Leonardo in the center of the table, where the tree stands. The support itself shows the signs of the preliminary interventions Leonardo made when he started realizing the piece of art: indeed, holes and incisions, which modify the original project, first outlined on paper by the artist himself, are clearly visible. Furthermore, analyzing the pigments from the painting, some interesting data emerged: the drawing, first traced with a drypoint, was made with a black watercolor laid with a brush; instead, the bluish traces are performed by means of a dye from vegetable origin, probably an indigo; finally, the preparatory drawing was "sealed" by a very thin transparent layer consisting of a binder and a white lead. Only after having created this first preliminary layer Leonardo began layering the colours. The characteristic "velature" technique was realized by using a mixture of brown tonality pigments in fixed proportions along the entire painting; this means that the painter used a unique and homogeneous batch of pigments, possibly available at its shop. 

The restoration work, carried out together with diagnostic investigations, focused on the removal of several layers of materials from past restorations such as glues, pigment paints, touch-ups, etc. These materials, besides making the artwork difficult to read due to the oxidation and the consequent yellowing of the pictorial film, were also causing micro-lesions on the painting itself, because of the stretch operated by the degrading substances. Moreover, the already fragile pictorial film, was more endangered by the wooden support itself exposed to thermohygrometric variations, and by a central crossbar placed in a period following the realization of the work that prevented the wood natural movement, both determining different cracks and breakages of the pictorial surface with consequent fall-out of color. 

Today, after almost six years of intense work, it is possible to admire again Leonardo's masterpiece at the “Galleria degli Uffizi” in Florence: however, the painting is enriched by an additional cultural baggage, obtained thanks to the important diagnostic campaign supported by increasingly innovative technologies applied to the world of the cultural heritage.

Tiziana 

- http://www.opificiodellepietredure.it/index.php?it/868/leonardo-da-vinci-adorazione-dei-magi 
- http://www.opificiodellepietredure.it/index.php?it/1053/storia-tecnica-e-scienza-per-il-restauro-delladorazione-di-leonardo-da-vinci 
- http://www.opificiodellepietredure.it/index.php?it/870/progetto-di-ricerca-e-di-conservazione 
- http://www.opificiodellepietredure.it/index.php?it/871/ladorazione-dei-magi-e-le-indagini-scientifiche-oltre-il-visibile 
- http://www.opificiodellepietredure.it/index.php?it/872/i-primi-risultati-della-pulitura-settembre-2014