Pietro Pierotti a Skilled Moldmaker

Among the collection of one of the most precious and rich museum in the world, is the Cast Courts of the Victoria & Albert Museum in London, where are preserved many of greatest casts ever made. Each of them can be appreciated in many ways, of course the artistic one, the historical, the aesthetic, and not last the technical profile  Some, really monumental, such as the Trajan Column surmoulage by the mold maker Oudry or the Portico della Gloria in Santiago de Compostela, made by the famous Italian mold maker Domenico Brucciani, or also the Michelangelo’s David by Clemente Papi, Italian bronze founder and mold maker, attract our attention more than others. But each of them reveals a technical skills, great care of details and unprecedented quality of surfaces.

One of them in particular caught my attention during my recent visit and it is the full scale plaster cast of the St Peter Martyr’s Tomb of the Church of Sant’Eustorgio in Milan that the sculptor Giovanni di Balduccio sculpted in Carrara marble in 1339 and measures a height of 5.45 meters and a width of 2.75 meters.
The cast is showed in the Italian Cast Court and is an example of great craftsmanship and ‘Manual virtuosity’. Due to the large dimensions and composition complexity of the monument with its numerous planes, medium sized figures, high reliefs and caryatids on plinths, and the sophistication of ornate surfaces, it’s easy to imagine how complex was to make the mold on the original monument without any risks and damages. Last but not least, it was just as complicated to make that plaster cast of such a beauty.
The author is Pietro Pierotti a famous Italian mold maker active in Milan in ‘800. Unfortunately, Pierotti’s story is still little known and this is also one of the reasons that stimulated me to write about him in order to increase the knowledge on his technical expertise.
His workshop, much known at that time, continued later with his son Edoardo Pierotti and counted a very rich catalog of casts, coming partly from the Museo Campi and later on to form the famous Gipsoteca Vallardi (read another article on this blog).
Pierotti’s were specialists on casting burial monuments of the ‘300,’ 400 and ‘500 spread in the best cathedrals in northern Italy.
The official list of the Catalogo dei Monumenti, Statue e Bassorilievi e Ornamenti in Gesso di varie epoche formanti la Storia dell’Arte che si trovano presso Pietro Pierotti formatore delle Regie Gallerie of 1901 is very rich and counts a large number of monumental works as Certosa di Pavia, the church of Sant’Eustorgio, the Duomo and the Treasury of Monza. Then other casts from Bergamo, Brescia, Florence, Lucca, Bologna and Venice.
The tomb of St. Peter’s Martyr remains in the Catalog of the Gipsoteca Vallardi (1928) as well as a good part of the monumental cast collection that the Pierotti Bottega offered to their customers.
Other casts of the same workshop are present in the Victoria & Albert collection and among them also some pieces of the Gastone de Foix Monument by Agostino Busti called the Bambaja which in 1884 was made by Edoardo Pierotti.
Some valuable plaster casts are still preserved in the Gipsoteca of the Certosa Museum of Pavia in Italy. The making of a mold of this type requires a great deal of knowledge of the art of molding and a very accurate and intelligent organization of work.
The molding of the original marble has been made with molds in clay applyed in a careful work on each element, with the aim of not altering the marble surfaces and the original patinas, and damaging the marble which in some places is really minute and delicate as such as the little ‘kiosk’ with figurines and spikes placed on top of the sarcophagus. Thinking to the molding process we must imagine the size of each molds and their weight on such delicate marble. A scaffold system has certainly contributed to supporting the weights in order to prevent any damage.
The monument replica was made molding each single portions and volumes of the original tomb.
Particularly difficult was the molding of the undercover chamber, because it was enclosed inside the coffered ceiling and square columns, which did not allow a comfortable and easy work. Especially during the extraction phase of the larger portions of the mold.
It is important to remember that plaster during the setting phase develops heat and micro-volume expansion, if not well controlled, can break marble which is not elastic. Each mold have been perfectly designed so as to allow the exact reassembly of all pieces without any  error between the molds and pieces.
Once every single mold made with clay blocks has been completed, to avoid deformation due to the drying of the clay itself, plaster casts were immediately made.
We know that clay mold allow to get only one plaster copy so each element just casted in plaster was again molded with a definitive Gelatine Mold (animal glue) which was more durable over time and would allow to make other casts.
The cast must be provided with a solid supporting armor (in iron and wood assembled together) hidden exactly in the vertical elements represented by the statues on the plinths on the base. A slimmer armor was inserted into the columns that support the kiosk at the top. Likewise, every piece of plaster has been perfectly assembled to the great central sarcophagus, and the same for the statuettes on top and the kiosk with every minute figurine.
The masterpiece is then completed with an extraordinary care of the surfaces and a special attention to the reproduction of details rendered with absolute fidelity. The rich ornament of the frames and capitals with leaves and the beautiful patina that with a warm ivory tone embellishes the plaster, make the cast similar to the marble color.
The huge amount of work required for a cast of this type is legitimately confirmed by the high catalog price. Passed only by the monument of Gian Galeazzo Visconti in the Certosa of Pavia (1492-1562), with an height of 6 meters and 20 centimeters which cost 25.000 Lire; and from the Monument to General Bartolomeo Colleoni of G.A. Amado which cost 10.000 Lire; The tomb of Saint Peter Martyr was offered with the considerable price of 8,000 Lire in 1901.

Two pages of the original catalog (author’s collection).

On the right the signature of the master mold maker

Although a today’s confrontation is rather complex, due to the different organization of the work, different costs of artisans and materials and also the lower availability of specialized workers. Not last the different purchasing power of the current currency, but we can assume that the price would be around 120.000 Euro for plaster cast only. If we try to imagine the complete work with the same technique as the mold of clay (only very few professional mold makers still know this technique today) the price of the mold and plaster cast would reach 300.000 Euros (Making an approximate estimate).

A faithful replica project like that of St. Peter’s Martyr’s Tomb by Pietro Pierotti is to be considered as a work of exceptional skill that not all mold makers of that time would be able to accomplish. Made with the help of many workers, the complete work has certainly taken many months.

When we pass the gate and we enter inside the Italian Cast Court at Victoria & Albert we are attracted by the cast of David by Michelangelo which, with his elegance and monumental presence, seems to dominate all other casts.

But is interesting to considerate that under a technical profile the molding of David will be a really basic work in comparison to the great skill needed to make the cast of the tomb of St. Peter the Martyr. Only those who deeply know these technical aspects can immediately understand such great difference between different plaster reproductions. Based on these considerations, I can say that Pietro Pierotti, and his collaborators, are certainly among the   much skilled mold makers in their time, and the cast of the tomb of St. Peter the Martyr at V&A is a true art masterpiece, on this purpose proudly signed.

All photos by Andrea Felice 2017