The Materials And The Painting Techniques By Giulio Aristide Sartorio In The Pictorial Cycle “The Poem Of Human Life” (1906-07): Knowledge And Prevention For A Musealisation Project

Summary: In the spring 1906 Giulio Aristide Sartorio (1860-1932) accepted to create a large series of paintings on canvas to be placed in the Central Hall of the Venice Biennale of 1907: “The Poem of Human Life", a complex iconography, which sought the synthesis between the Greek-Latin and Nordic cultures. In the four main scenes – Light, Darkness, Love, Death and in the ten vertical Caryatids, Sartorio painted over 240 m2. To complete the cycle in just nine months, he used a special painting technique, fast enough, which he describes as follows: "I used a mixture of wax, mineral turpentine and oils”. Sartorio, in fact, was known to work with hand-made mixtures of oil paints (mixed with pigments and produced by himself in the atelier) with several waxes, natural resins, mineral spirits and gums. This cycle has been undergone a complicated conservation history since its first moving from Rome to Venice by train by the end of 1906. The entire cycle was transported back to Rome, where it remained until the early 1950s and then back to Venice. Those frequents transfers implied the folding and rolling of the canvases. In the Ca’ Pesaro museum the cycle was partially exhibited, up to the mid-1980; then it was stored in an exhibition room used as an interim storage room for several works of art until 2009. The painting cycle has been almost inaccessible and exposed to a large amount of dust and to inadequate conservation conditions. Once "liberated" in 2011, different degradation phenomena were observed: small lacunae on the pictorial layers; the presence of large brown spots of mycotic origin; wide-spread craquelures; efflorescences; the flattening and the bruising of painted layers (in some areas the paints are more than 1 cm thick); physical damages of the wooden frames. A conservation and maintenance project was needed to access and protect Sartorio’s paintings. The first step of the conservation project involved the study and the characterisation of the entire cycle to identify the materials and the paintings techniques adopted by the artist and to understand the degradation processes which the paintings underwent to. The microscopic, Fourier-transform infrared spectroscopic (FT-IR) and gas chromatography-mass spectrometric (GC-MS) analyses suggested that Sartorio used primed canvases presenting a lead white/linseed oil-based ground layer. Furthermore analyses by GC-MS confirmed that the cycle was painted out by mixing drying oils and beeswax, according to the painting technique declared by the artist himself. The artist’s palette consisted in traditional and modern pigments, such as burnt Sienna , yellow ochres, bone black, lead white, zinc white and ultramarine blue. In particular, it was found out that linseed oil was the binder for dark colours, while poppy seed oil was detected in correspondence with white and blue pigments, probably to avoid the more yellowing effect caused by the former oil. No varnishes were applied on the painted layers. The presence of paraffin wax and watercolours, detected by FT-IR and GC-MS in several damaged areas, are due to previous consolidation and retouching treatments. Several degradation products were identified, such as the formation of metal soaps (lead carboxylates) migrating from the lead/oil-based grounding to the upper layers. Nowadays this extraordinary painting cycle is located in the new deposit of the Museum, where it is undergoing a necessary maintenance and it looks forward to returning to Ca 'Pesaro to be exposed. The knowledge of the materials and of the techniques used by Sartorio gives here the possibility to suggest few general guidelines for a correct musealisation, considering as a priority the prevention of future degradation processes, which are usually due to the conditions of exhibition themselves and an excessive exhibition stress. This research show that any musealisation project must consider the specific technical and material characteristics of the artworks prior their exhibition.