MADRID.- The Thyssen-Bornemisza Museum has completed the technical study and restoration initiated more than a year ago of Canaletto’s painting The Piazza San Marco in Venice.

This project has been possible through a pioneering “micro-sponsorship” crowd-funding campaign launched in June 2018, which raised the required 35,000 Euros in barely four months. For the purposes of the campaign the painting was divided into 1,000 sections, each with a symbolic value of 35 Euros, which was the minimum contribution and which allowed many people to contribute by acquiring a “little piece of Canaletto”.

Painted between 1723 and 1724, The Piazza San Marco in Venice is a magnificent early work by the Venetian artist, considered the most important of the 18th-century Italian vedustiti or view painters. It is also one of the few works by Canaletto in a Spanish museum and one of the most representative of his style and finest quality.

The procedure undertaken by the museum’s restoration team has principally consisted in returning the painting to its original state as far as possible, given that it showed considerable deterioration due to the passage of time as a result of earlier restorations and the presence of various layers of oxidised varnish and areas of repainting. These concealed the work’s luminosity and the original colours beneath a yellow veil.

Having carried out the corresponding technical study prior to embarking on the restoration in order to decide on the most appropriate method and means to be used, the museum’s restorers removed old varnish and areas of deteriorated repainting while also reintegrating some areas of paint loss.

This has been a complex and delicate undertaking due to the damaged and altered state of the pictorial layer, particularly in the darkest zones and due to the presence of old areas of repainting and different layers of oxidised varnish. For this reason, the entire restoration process has benefited from a supervisory procedure by the museum’s laboratory, which evaluated the risks of intervention at each moment. This allowed for any necessary adjustments to be made to the working method and the techniques employed on the basis of the results obtained.

The painting was relined at an unknown date and its original size was altered, with around 2cm of the canvas folded over the stretcher at the top and another 2 cm added at each side, modifying the original dimensions.

The final result has reinstated the morning light and subtle nuances that Canaletto gave to his work. The cleaning has also revived the crispness and precision of the numerous details in the composition, such as the figures, either alone or in groups, the architectural and ornamental elements, the market stalls with animals and other objects, etc.

Some small details that were difficult to see with the naked eye have now reappeared and can be appreciated in the macrophotographs taken. These images bring us closer to Canaletto’s working method and to his mastery in the depiction of minute details, painted with rapid but very precise brushstrokes.

Technical study
Through the use of micro-samples, pigment analysis, stratigraphy and X-radiography the museum’s restorers were able to reconstruct the creative process behind the work and learn more about this great Venetian master’s way of painting. Over the original canvas, which is linen with a taffeta weave, he applied an initial layer or priming of a reddish-orange tone made from a mixture of earth pigments bound with a drying oil. Visible on top of this layer are some very fine, light lines applied with organic charcoal which may have functioned to define different areas that structure the composition.

The artist then applied large areas of paint which acted as the ground to the different spaces defined within the painting: a grey ground for the sky, a yellowish-brown one for the brightest areas in the Piazza and its buildings, and a blackish-brown ground for the darkest buildings or those in shadow.

Over these large areas of colour Canaletto applied the oil, which reveals mixtures of high quality pigments such as white lead, Prussian blue, Naples yellow, vermilion, red lake, charcoal, bone black and a wide range of earth pigments in red, umber, orangeish and green tones.

Visible in specific areas, such as the cluster of the basilica’s domes, are lines drawn over the paint which reinforce the volumes of the final composition.

X-radiography
The images obtained with Xradiography have provided interesting information on Canaletto’s working method. Particularly notable are the marks left by the pair of compasses which the artist used to position the four decorative arches on the upper part of the bell tower, with a corresponding hole in the centre of each one and the incised line of each curve. While the use of this instrument by painters was not unusual, its employment on top of the paint layer is striking.

X-radiography has also shown how Canaletto concealed some of the clothes hung out between the arches of the façade of the Procuratie vecchie using the final paint layers. He also made some changes to the chimney, altering its proportions, and modified the overall lighting of the façade which he initially conceived as slightly darker.

The different densities of the pictorial layer that are evident in the X-radiograph reveal the very deliberate application of each single brushstroke, none of which are random, and the way in which Canaletto was perfectly able to depict complicated architectural structures such as the cluster of domes. Using a rapid, loose brushstroke he reproduced even the smallest details, demonstrating the remarkable effectiveness of his technique.

Infra-red reflectography
Infra-red reflectography shows the underlying lines which define the composition’s perspective. These lines are part of the creative process of the painting and are visible beneath some of the figures.

In addition to these principal lines Canaletto added others that allowed him to position the architectural structures. This is evident in the frontal façade which shows the grid that the artist used to position the windows. He subsequently added semicircular tops to one of these lines of windows and also varied the position of some of them.

Changes are also evident in the distribution of the circular windows in the top level of the Procuratie vecchie below the cornice, many of which Canaletto slightly shifted in relation to his original design.

Perspective
Canaletto depicted the celebrated Piazza San Marco in Venice using an architectural design based on the mathematical value of proportions and the manipulation of perspective, in which the final result is based on unifying different viewpoints. He firstly divided the painting in half vertically, establishing two symmetrical vanishing points on a horizontal axis, both at the same distance from the centre of the composition.

The similarity between the painting’s orthogonals and the real image of the Piazza allows us to assume that Canaletto used a camera obscura in order to translate the different architectural elements onto his canvas. Nonetheless, the perspective that he created is not based on a direct image but on the manipulation of different viewpoints obtained in the Piazza in order to create a theatrical space that is more enclosed than the real one, in the manner of a stage set.

Interactive screen and publication
The painting, now reinstalled in Room 17 of the permanent collection, is accompanied by an interactive screen with images and explanatory texts that allows visitors to discover and learn about all the details of the technical study and restoration of the painting, its process of creation and Canaletto’s working method.

A knowledge of the techniques and materials used by artists is fundamental for establishing procedures aimed at halting the deterioration of works of art. Looking into the most detailed aspects of the creative process also allows us to enter the mind of the artist and his time and to understand the creative act and its context on the basis of more concrete information. All these aspects are covered in a publication produced by Artika publishers, whose contribution to the crowd-funding campaign brought the total raised to the amount required to undertake the restoration.