Spanish sculpture of the last third of the 19th-century and first third of the 20th century was frequently of a high level of technical virtuosity and excellent artistic quality, and the Museo del Prado has various masterpieces of this kind. The National Fine Arts Exhibitions provided the context for the display and dissemination of such works. Eduardo Barrón (Moraleja del Vino, Zamora, 1858 – Madrid, 1911) participated in the 1904 exhibition with the sculptural group Nero and Seneca, winning a First Prize Medal (photo, E-586).
In addition to being one of the leading sculptors of the day, Barrón had been Curator of the Sculpture Department at the Prado since 1892, also becoming its Restorer in 1895. He thus wrote the first catalogue of the Museum’s sculpture collection, entitled Catalogue of the Sculpture (1908), which provided information on the Museum’s sculptures up to the 18th century, given that those from the 19th and 20th centuries had passed to the recently created Museum of Modern Art (MAM) in 1896.
This group depicts Seneca instructing Nero, to whom he was tutor. Barrón focuses on a dramatic expression of their different characters, hinting at the unjust fate of the Cordoban philosopher Seneca, who would be accused of treason and obliged by the Emperor to commit suicide. That event is depicted in other works in the Museum such as The Death of Seneca by the studio of Rubens, and the painting entitled Seneca in the Bath, having opened his Veins, while his grief-stricken Friends swear their Hatred of Nero who decreed their Master’s Death by Manuel Domínguez Sánchez.
The group is executed in plaster which, according to images obtained using an electronic sweeping microscope, consists of two layers of a different texture, the upper layer more compact than the lower one.
The most unstable areas of the greatest structural complexity were studied using x-rays, which provided information on the different internal structures (pins, nails, screws, wire) present in the work, its state of preservation and the original process of creation.
Through the micro-samples analysed it has been possible to identify areas of different materials that were subsequently applied during previous restorations, such as bees’ wax, synthetic acrylic resins, micro-crystalline wax and animal size, all applied in specific zones. This information has been used to determine the materials required for cleaning the work.
The original polychrome only covered specific areas of the sculpture, particularly Nero’s cloak, in addition to the scroll holder and part of Seneca’s clothing. The polychrome areas have an initial layer that functions as a base made of red ochre and animal size, over which the artist applied a mixture of pigments: barium white, zinc white, red ochre and minium (red lead), bound with linseed oil.
The decoration of the collar and edge of Nero’s cloak originally appeared golden due to the application of metallic powder (an alloy of copper and zinc), to which an oil patina was applied to tone down the shine. Prior to restoration this gold appeared dark green in colour due to the oxidisation of the copper.
Other materials identified include vegetable and wood fibres used in the interior of the work to give greater stability and resistance to specific, fragile elements, as well as paper used to give the impression of leather covering the scroll holder for aesthetic purposes.
The group’s state of conservation prior to restoration was not ideal, due to both the inherently fragile nature of the material of which it was made and the inappropriate conditions in which it had been kept and displayed.
The support had dried out considerably and revealed cracks and fractures, particularly on the base. In addition to these small losses in the ground area, the fingers, edges of the folds and the most prominent areas, the work had been vandalised and showed the marks of numerous cuts and graffiti.
Previous restoration had resulted in losses being made up with very hard areas of stucco covering the original surface, protective layers applied in a partial manner that had penetrated the material in an irreversible manner, and some poor quality, volumetric reconstructions. All this meant that the quality and state of preservation of the work was notably uneven and depended on the area in question.
The problem of designing a particular restoration treatment for this sculpture related to the fragility of the material (plaster) and to the amount and variety of earlier restorations to which it had been subjected. In order to establish a correct and effective solution and in addition to the above-mentioned technical studies, exhaustive solubility tests were carried out in different areas to determine the products and cleaning techniques that would be most appropriate in each case.
The principal cleaning of the work was carried out using agar-agar gels, a product derived from different species of marine algae that form gels which retain large amounts of water in low concentrations. These gels have extremely powerful cleaning properties through the controlled application of moisture and absorption of dirt without the need for rinsing. Their use is therefore highly recommended for the application of aqueous treatments to delicate and partially soluble surfaces such as plaster.
The treatment was completed with various types of mechanical cleaning (India rubbers of different degrees of hardness and even the micro-projection of vegetable abrasives at low pressure). Chemical cleaning was also necessary in specific areas in order to remove stains and accumulations of previous additions to the surfaces. Mixtures of organic dissolvents were thus applied as strips with protective paper in between and the application time strictly controlled. The aim of these procedures was to restore a homogeneous appearance to the surface of the work, respecting the natural aging of the material used to create a sculpture that is now more than 100 years old.
In addition, all poorly executed areas of reconstruction were removed. Many of them were not fully attached to the original surface and had been reinforced with nails that had produced stains due to oxidisation. Following a criteria of minimum intervention it was decided only to reconstruct the fingers of Seneca’s right hand on a scale proportionate to the rest of the work, given that they are located at the work’s focal point and because they are important to the figure’s expressive powers and thus to the narrative being recounted. In addition, the original areas of polychromy have been left as they are in the present day, without touching the areas of oxidised metallic powder.
In order to recreate the fingers, the Museum’s restorers turned to the original, reduced-scale model now in the Museum in Zamora, from which digital data was obtained and enlarged to the appropriate scale. Old photographs that showed the work with the original hand still intact were also consulted. Reconstructed areas that harmonised with the work were retained.
Losses were filled in with gesso and were chromatically reintegrated using reversible materials such as watercolour and gouache and techniques visible to the naked eye such as pointillism and trateggio.
The sculpture had previously been on deposit with the Town Hall of Cordoba and the City Council wished to possess a version, so a replica was made of it. Given that the original was made of polychrome plaster, the traditional reproductive method involving direct moulds was completely impossible due to the high risk of loss to the colours and surface textures.
A replica was thus made using digital scanning, in which an exact resin model is created through a 3-dimensional image from which a mould is made. The resulting replica cast from the mould is now to be seen on the Glorieta del Pretorio in Cordoba.