FF owns a nice midcentury example of a technically challenging type of glass. Sommerso, or “submerged,” a technique developed in Murano Italy in the 1930s required skill and dexterity. His vase is in three colors of glass, amethyst to cobalt to crystal clear, and stands at eight inches tall. It weighs quite a bit, as many layers of glass create a thickness of a one inch wall which grows to two to three inches as the vase tapers to the base.
The base sits completely flat, which means the glassmaker polished the base to eradicate all traces of a lumpy pontil mark. A pontil mark is a scar left behind when the glassblower breaks the pontil rod, the tube that carried his breath, off the finished glasswork. Some glass pieces have an indented saucer shaped polish mark on the base. Some pieces, likely the lighter glass goblets, have no polished pontil, and will show the rougher break at the bottom of the cup. Most high value Murano vases have glass bases polished flat on the foot, especially those heavier Sommerso pieces. Not to polish a pontil flat compromises the balance of the work of art.
What is Sommerso Glass?
Sommerso involves submerging a blown glass piece into molten glass of another color. A maestro like Carlo Scarpa initially blew an inner core vessel. Then he dipped it in a pot of molten glass of another color, and sometimes repeated this process on another three or four layers. During the process, the existing base, or glass pieces as the work develops, may shatter when placed in the glass blown around it.
An artist needs a good mind for weights and balance because multiple thick layers of glass make the vessel heavy. They create further artistry by adding gold leaf to the clear layer of glass on the outside, or sections of bubbles in the glass in the deepest section, or striped rods of multicolored glass blown in the center or base to add depth and intensity. The illusion creates gravity-defying colors that lay on each other without the slightest hint of mixing at the borders.
Another Maestro of this Technique
Flavio Poli, Artistic Director of Segusa Vetri d’Arte, made Sommerso famous. His midcentury creations fetch thousands of dollars. Not all Sommerso glass is by Poli, however. Other furnaces in Murano made this type of glass. Mandruzzato, Formia, and Paolo Venini, all worked in the 1950s. Present day masters include Obali/Oggetti, the Onesto Family, Cenedese, Venini, and Barovier Toso.
All Murano artists’ predecessors came to the Island of Murano in the 13th century. At that time, the Glassblowers Guild was removed from the island of Venice, because the buildings of that watery city couldn’t withstand the prolonged high temperatures of the glass furnaces. The City Fathers moved the Venetian Guild, operated under strict rules and secret formulas and undisclosed techniques, to Murano. Venice glassblowers active since the 8th century, under Roman occupation, and Byzantine artists brought the formula of glass making to Venice.
Challenging Yellow/Green Glass
Perhaps the most challenging technique used in Sommerso colored glass is a color between lime green and yellow. When seen under ultraviolet/UV illumination, it glows. You see stunning photos of the greenish glowing glass when shot with 365nm illumination. We identify the presence of uranium by exposing it to black light as well. Uranium glass, sometimes called Vaseline glass in England and the US in the early 20th century, was first used to color glass in the 1910s till the period after the mid 1950s, when Murano began to experiment with the color. The US, because of WWII and the Cold War, banned uranium oxides and salts from commercial use and didn’t allow production of uranium glass.
Early pre-1950s uranium glass reached an order of 25 percent radiation per weight of the vessel. After 1950, two percent. An interesting museum tracks household objects, toys, and such things as uranium glass dinner plates, estimating the radiation exposure we all had from our early 20th century commercial products. This institution is the Oak Ridge Associated University’s Museum of Radiation and Radioactivity.
Not only is FF’s Sommerso glass beautiful but thankfully it contains no yellow/green glass! The value is $500.