Large rectangular table box in gold-plated 925/1000 sterling silver with translucent enamels fired on guilloché and a fine miniature of a bouquet of flowers hand-painted by the painter Romano Buccioni. In early 1900s English Art Nouveau style. Dimensions: 10 x 13.3 cm, height: 3.5 cm. Weight: 743 g. Designed by Renato Salimbeni in 1940, inspired by old artifacts manufactured at the Salimbeni company headquarters in Florence, and always produced by Salimbeni in a single example, entirely hand-crafted by artisan artists with a thick plate and large reinforcements suitable for withstanding numerous enamelling firings at high temperatures at around 800° C.
GUILLOCHE: This is a handcrafted process performed on mostly precious metals, resulting in surfaces engraved with complex, repetitive geometric patterns.
Guilloche engraving was invented in the mid-19th century in Switzerland by watchmakers to embellish the dials of their luxurious timepieces.
The technique involves engraving metal with a burin using a machine with mostly manual controls.
A copying tool, following the curves of several dies placed on the machine, transmits movement to the object being engraved, causing the burin to "cut" the metal. By shifting the positions of the dies and the copying tool, precise, intertwined geometric engravings are obtained, creating an almost infinite number of patterns, and their continuous differentiation certainly adds value to the objects produced.
The manual skill required to perform this operation is highly specialized; existing machines are very old, as there has never been a mass market, and especially for art conservation.
After engraving, the next step is typically firing enameling, a meticulous and time-consuming process in which the guilloche-engraved surface is covered with several layers of colored glass powder and fired in small special kilns at temperatures between 700 and 800°C.
The resulting transparency and perfection may require numerous firings, especially if multi-colored surfaces are being composed.
The inclination of an object's surfaces can create significant difficulties both for guilloche engraving and during the enamel firing phase, as positioning the machine becomes more complex and requires great skill and expertise, while liquefying the enamel produces complex situations that only highly skilled artisans can achieve.
Guilloché engraving and enameling have been the core processes of Salimbeni 1891 for over a century and are found in nearly all of its products.
When crafting an object, Salimbeni 1891 begins with a drawing, which can also be provided by the customer, to handcraft the structure using silver sheets of varying thicknesses. Once the required shape has been achieved through welding and finishing-processes common to skilled silversmiths-the next step is the guilloché engraving and subsequent enameling, as well as all the final polishing and electroplating processes for gilding and/or other applications.
Our most complex and precious creations have required months of work for smaller objects, striving for a perfection that is generally not contemplated in artisanal work but which for us is the foundation of our daily lives.
ENAMEL
English: enamel
French: smalt
German: schmelzen (to melt)
A glassy substance consisting of a mixture of silicates, potash, silica, soda, red lead, quartz, feldspars, borax, and minerals containing metallic phosphors, as well as numerous metallic oxides.
The enamel base material is prepared in melting furnaces into which the aforementioned ingredients are added. The mass is heated to temperatures varying, depending on the situation, between 1000° and 1200° C until molten glass is formed; this is followed by rapid water cooling. At this point, the material is finely ground, known as "frit."
The color of the base material is obtained by adding metallic oxides, which, in varying percentages, do not compromise its transparency. These are mixed with the "frit" and then thoroughly washed with distilled water to remove any residual impurities from the powder. The whole thing is then melted again and poured into molds to store it in blocks. Before use, it must be finely ground again and washed with distilled water. There are approximately 700 different colors of enamel, but in practice today, use is limited to about two hundred. However, layering the different colors allows for a virtually infinite range of combinations and shades, which can range, even on the same object, from darker to lighter shades and vice versa.
THE CONSTRUCTION OF A SILVER BOX, even a very simple cubic or parallelepiped shape, is always a particularly complex process, especially if the subsequent embellishments required after achieving its shape require engraving, carving, guilloché, and various high-temperature firings, as in the specific cases of fire enameling.
Silver sheets in various thicknesses are supplied as semi-finished products by precious metals mills that melt the silver to the required fineness, in continuous castings that are rolled through cylinders in machines specifically designed for this purpose. The sheets normally have standard dimensions of 50 x 150 cm.
For boxes that will be fire enameled, the sheet thicknesses vary from a minimum of 10/10 to 15/10.
The sheets are cut to size with milling machines or pantographs and "chiselled" along the edges, which must be bent to obtain perfectly sharp and square angles, or bent with the aid of various devices to obtain rounded, rounded, or curved edges.
The matching edges must be welded using solders, which, in the case of enameled work, must be highly resistant to withstand the high temperatures to which they will be subjected later. The law on precious metals requires that silver solders must always contain silver in the alloy, to prohibit "tinning" or other non-precious metal alloys.
The object that has become a "container" must be reinforced along the edges so that subsequent exposure to high temperatures does not deform it. For this purpose, silver "squares" are used, i.e., square or rectangular wires a few millimeters thick that are soldered to the tops of the various sides.
Using a precisely sized half-round cutter, the groove is created for the various hinge segments, which will be welded alternately to the lid and the bottom.
To create a "lost hinge," or semi-invisible hinge, larger and thicker hinges are used so they can be filed down to the same height as the box's side plate.
For spherical or cylindrical boxes, the plates are machined using lathes, but often the plates are forged by compressing them with suitable polyurethane rubber "sharps" using hydraulic presses. This helps shape the object, but perfect fit must always be achieved by hand.
Once the box is completed with the addition of snap closures, notches, and so on, the design phase begins, with the carving of the enameled recesses and the guilloche work on the surfaces beneath the enamel. To do this, all the contours are drawn with a burin, and with the aid of compasses and steel rods, all the areas where the enamel will be applied are hollowed out, using both guilloche and manual tools, for approximately 3.5/10 cm. Finally, the areas where the enamel will be applied are incised, again using guilloche or manually.
After enameling, which involves numerous exposures to temperatures around 700° < 800° C, the silver oxide that has formed must be removed and the metal smoothed, before moving on to the final polishing and electroplating.