Who among us who while wandering around an historic art collection hasn’t been struck by the use of gold in Medieval paintings, by their golden backgrounds or the minute golden details of the gowns and those of the different hairstyles of the many characters depicted? Who among us hasn’t been drawn to the twinkle that results from the combination of gold and light?
Human beings have always felt a kind of deep fascination towards gold, raising it as the symbol of cosmic immateriality, of the sun, of the pagan deities, and, eventually, of God. Gold is one of the most ductile, flexible and durable materials and it has always been very appealing to all sorts of craftsmen. It is therefore completely understandable that Medieval painters made extensive use of this particular element: other than being such a malleable material, gold helps to bring the mysticism of the painting to a greater level.
Among the works in the Acton collection, one of the paintings that makes the most of gold’s features and gives us the sense of the great symbolic value attributed to gold during the Middle Ages is the Coronation of the Virgin by the Florentine painter Mariotto di Nardo, executed in the very last years of the 14th century (fig. 1). The original location of the painting is unknown, but we do know that it has been part of the Acton collection since the 1920s and that it has always been hanging in the Sala da Pranzo, the big dining room where the Acton family had lunch, surrounded by masterpieces of the 13th and 14th centuries, a sort of Sancta Sanctorum within the collection.
Let’s get a closer look at the painting. Christ and the Virgin are placed inside a golden mandorla, a lozenge-shaped aureole of light: the Son is depicted right in the act of crowning his Mother, who is sitting down, leaning towards him, as “Queen of Heaven.” A group of cherubs is flying over their heads, looking down at them, while five more angels are kneeling down at their feet, attending the holy scene. Four saints are depicted on either side: Saint John the Baptist, wearing his camel skin, Saint Catherine of Alexandria, with the wheel of her martyrdom and the martyr’s palm, Saint James the Great, recognizable by his pilgrim’s staff, and Saint Lucy, with both the lantern and the martyr’s palm.
The painter illustrates a great event taking place in Heaven: the depicted characters are standing upon star-studded clouds and are standing out against a golden background, suggesting the holiness and the marvelous nature of the event. The typical golden background (fig. 2) is carried out in the water gilding technique: the gesso ground of the wooden panel painting is covered in a layer of bole, a greasy-textured clay that acts as adhesive for the gold leaf. Once the gold leaf is laid on the bole, it is burnished, that is it is rubbed with an animal’s tooth or a hard stone both to make the various layers stick together even tighter and to smooth the gold leaf, making it brighter.
Interestingly enough, the cherubs on the sides of Christ and the Virgin are realized by light brush strokes of translucent varnish (vernice traslucida) directly applied on the gold background, so that its typical warmth and brightness would arise through the thin impressions of the brush (fig. 2). By doing so, Mariotto is able to restore the immateriality and the airy consistency of these celestial beings: the other characters are in fact carried out a different technique, in egg tempera, which is laid directly onto the gesso ground of the wooden panel.
The paint itself, and not only the paintings’ background, is also enriched by infinite golden details: gold leaf is used for the kneeling angels’ wings, for the hems of the different capes and gowns, and for the haloes that adorn the various characters of the scene. The leaf is minutely punched and tooled, that is decorated with patterns of incised lines and decorative ornaments using the gilders’ tools (styluses and punches).
One of the most wonderful decorative patterns of the painting is the gilded one, which stands out against the light background of the Virgin’s gown (fig.3). It has been realized using the so-called sgraffito technique: a layer of egg tempera paint is applied onto the gold leaf so that you can’t see any golden bit once you are done. Then, the pattern you want to decorate the gown with is outlined and you scratch the egg tempera paint away according to the set pattern. It’s one of the most delicate and meticulous gilding processes and it has to be carried out with the utmost mastery. Once the paint has been scratched away – graffiare is the Italian for scratching, hence sgraffito – revealing the gold beneath it with a stylus, which is one of the main gilding tools to be found in a Medieval workshop, the pattern is finally revealed.
A very similar decorative golden motif is to be found on the coordinated cape the Virgin is wearing on top of the gown. This time, though, it is carried out using a different gilding technique (fig. 3): the golden pattern is very similar, as is also the light color of the cape that acts as the background of the golden decoration, but this time the gold leaf has been laid on top of the egg tempera paint rather than beneath it. This technique is known as mordant gilding. The background of the cape has therefore been depicted in the typical egg tempera paint. On top of this layer of paint, the artist has outlined the pattern that he is going to gild: using a brush, he has applied a mordant, that is a sticky mixture that is going to act as an adhesive for the gold leaf. Once the leaf is laid on the surface, it will adhere only to the bits that had earlier been brushed with the mordant and that outline the desired pattern, while the rest of the leaf will be swept away.
Mariotto has therefore used the gold leaf in various ways: in the water gilding of the background, in the sgraffito motifs of the Virgin’s gown (with the egg tempera paint covering the underlying gold leaf), and in the mordant gilding of the decorative pattern on the Virgin’s cape and on the hems of the various cloaks worn by the other characters (with the gold leaf covering the underlying egg tempera paint). In each of the cases we discussed, the painter used the gold leaf: but how is this leaf obtained? And where does it originate?
Starting in the 13th century, gold leaf was obtained directly from golden coins. These were first melted, reshaped, then placed on a wide stone and beaten with a hammer until they had reached an infinitesimal thickness. The reason why golden coins were used as the source for the making of the leaves is explained both by the ease of their procurement and by the guarantee of the purity of the gold that composed them, since this was scrupulously controlled by the State Mint. Historical sources mention that the leaves were produced in square shapes and that they had a thickness significantly less than 1 millimeter, about 3 nanometers, that is around 0.0003 millimeters. Today, the squared shape of the leaves is often very distinguishable in those paintings whose’ golden background has been worn by the passing of time. If you are a thorough observer, you will have easily noticed the perimeter of the background golden leaves of the Coronation of the Virgin by Mariotto (fig. 2).
Nowadays, when we gather around a Medieval or Renaissance painting displayed in a museum itinerary or in a church illuminated with electrical light, we have to remind ourselves that the same paintings we are seeing were originally intended to be looked at in natural daylight, the light that came in from the windows, or the artificial light produced by torches and candles that emitted a much more unstable and unmanageable light, but at the same time a more fascinating and mysterious one than what we are used of today, emitted by electric light bulbs. That kind of light was supposed to release a very moving sparkle when it scattered itself upon the gold leaf of paintings such as the Coronation of the Virgin by Mariotto, carrying the observer into a surreal world.
The holy scenes depicted in Medieval paintings would, therefore, not only tell a story to the viewer, but were also meant to recreate the miraculous event they were telling in front of his or her eyes, thanks to the mystic fascination released by the gold, illuminated by candlelight. The Actons chose at first to enlighten the rooms displaying their art collection with those same candles and, when electricity became available at the beginning of the 20th century, they used the finest light shades made out of glass beads to cover the modern light bulbs, recreating the same sparkly effect made by the candlelight that had previously struck the gold in the paintings.
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