Stringer stacking, otherwise known as Moretti’s Technique (1873-1924).
The procedure behind the murrina portraits complex and tedious work. The final images are obtained by putting many thin, differently colored glass rods side by side to form a cylinder (called massello) about 4 inches in diameter and 9 inches long. Thus the pattern ran all the way down the inside of the massello: on the front was the desired picture, on the back its mirror image, as in a slide. The cylinder, tightly bound with a copper wire, was slowly heated at the furnace mouth and, when the glass reached the right fluidity, was pulled to become a long rod. The various cross-sections of this rod, cooled and cut into small rounds, are the artistic murrine – and therefore the portraits – just as they have been handed down to the present day.
Today much of the historical and experimental research carried out by Vincenzo Moretti forms the foundation of the present-day working of modern murrino glass: his “palette” of compatibility of glass and colours, whose purpose – when different vitreous components were put side by side – was to avoid breakages during the cooling process, is still one of the clearest examples of the boost he and his family gave to present-day glass-making on Murano.
Whilst Vincenzo Moretti (1835-1901) produced the most important examples of glass made using this technique, it was Giovanni Battista Franchini (1804-1873) who invented thinner and more complex millefiori rods, abandoning the traditional star and creating new designs; with these his son Giacomo specialized, resulting in amazing miniaturized portraits that were mainly dedicated to the most famous people of that period (Pope Pius IX, Emperor Franz Joseph, etc.). This virtuoso and exhausting work truly put Giacomo to the test, so much so that he went mad: thus in 1869 his father was given an award in Murano, as if he were being compensated “for the amazing invention of the rod portraits that caused him the almost irreparable loss of a son…”