Introduction
Of all the techniques developed in the long history of decorative glassmaking, few are as immediately arresting as sommerso. The Italian word means simply ‘submerged’, and the technique it describes — encasing one or more layers of coloured glass within a clear or differently coloured outer layer — produces objects of extraordinary visual depth and luminosity. A fine piece of sommerso glass seems to glow from within, the submerged colour suspended in the surrounding glass like a jewel in ice, its edges softened and its brilliance amplified by the refractive properties of the encasing crystal.
Sommerso was developed to its highest expression in two distinct but related traditions: the Murano glasshouses of Venice, where the technique was refined in the mid-20th century into some of the most celebrated objects of Italian design; and the Scandinavian glasshouses of Sweden and Finland, where designers working in a parallel tradition produced sommerso-influenced work of comparable quality and distinction. Together, these two traditions define the golden age of sommerso glass — the decades from approximately 1930 to 1970 — and the finest pieces from this period are now among the most actively collected objects in the mid-century decorative arts market.
The Technique: How Sommerso Is Made
Sommerso is a gather-within-gather technique. The glassblower begins by gathering a small amount of coloured glass on the blowpipe and partially inflating it to form the inner layer. This gather is then dipped into a pot of differently coloured or clear glass, encasing the inner layer in an outer shell. The process can be repeated multiple times to build up several distinct layers of colour, each separated from the next by a clear or coloured interface.
The key to the technique is the precise control of the thickness and distribution of each layer. The glassblower must manage the viscosity of each gather, the timing of each dip, and the inflation of the composite gather to ensure that the layers remain distinct and evenly distributed throughout the finished piece. In the hands of a master, the result is a vessel in which the colour layers are perfectly controlled — each layer of consistent thickness, the boundaries between layers sharp and clean, the overall form expressing the colour relationships with maximum effect.
The finished piece is typically fire-polished to a high gloss and may be further worked — cut, ground, or engraved — to reveal the colour layers in section and create additional visual effects. Cut sommerso, in which the outer layer is cut away in geometric patterns to reveal the inner colour, is one of the most dramatic expressions of the technique.
Murano: The Italian Tradition
The island of Murano, in the Venetian lagoon, has been the centre of Italian glassmaking since the late 13th century, when the Venetian Republic ordered all glassmakers to relocate there from the city of Venice — ostensibly for fire safety reasons, but also to concentrate and control the glassmaking knowledge that was one of Venice's most valuable commercial assets. For seven centuries, Murano has been the source of the most technically ambitious and aesthetically influential glass in the world.
The sommerso technique was not invented in Murano — the principle of encasing coloured glass in clear glass has ancient precedents — but it was in Murano, in the mid-20th century, that the technique was developed into a fully realised artistic language. The catalyst was the extraordinary creative ferment of the post-war period, when the Murano glasshouses — recovering from the disruption of the war years — entered into a series of collaborations with designers and artists that produced some of the most celebrated objects of Italian modernism.
Flavio Poli and Seguso Vetri d'Arte
The central figure in the development of Murano sommerso is Flavio Poli (1900–1984), the artistic director of Seguso Vetri d'Arte from 1934 to 1963. Poli was not a glassblower but a designer — trained as a ceramicist and sculptor — and his approach to glass was fundamentally sculptural. He was interested in glass as a material with its own inherent aesthetic properties, and he saw the sommerso technique as the ideal vehicle for exploring those properties.
Poli's sommerso pieces for Seguso are characterised by their bold, organic forms — heavy, asymmetric vessels that seem to have been shaped by natural forces rather than human hands — and by the extraordinary depth and luminosity of their colour. He worked primarily with two or three colour layers, typically combining a deep, saturated inner colour — amber, green, blue, or red — with a clear or lightly tinted outer layer that amplified the inner colour's brilliance without obscuring it.
Poli's most celebrated works are the Valva series — asymmetric, shell-like forms in sommerso glass that won the Grand Prix at the Milan Triennale in 1954 — and the Corroso series, in which the outer surface of the sommerso piece is treated with acid to produce a matt, textured finish that contrasts with the brilliant colour of the inner layers. These pieces are among the most sought-after objects in the Murano glass market and command very significant prices at specialist auction.
Poli's work for Seguso was produced without individual signatures — Murano glasshouses of the period typically did not sign individual pieces — and attribution relies on comparison with documented examples, exhibition records, and the Seguso archive. The collector should be aware that attribution of unsigned Murano sommerso to specific designers is a complex field requiring specialist knowledge.
Other Murano Makers
While Poli and Seguso are the most celebrated names in Murano sommerso, other glasshouses and designers made significant contributions to the tradition:
- Archimede Seguso — who left Seguso Vetri d'Arte to establish his own glasshouse in 1946 — produced sommerso work of great refinement, often combining the technique with other Murano decorative traditions such as merletto (lace glass) and filigrana.
- Venini — the most internationally celebrated of the Murano glasshouses, Venini produced sommerso work under the artistic direction of Carlo Scarpa in the 1930s and 1940s. Scarpa's sommerso pieces for Venini are among the earliest and most historically significant examples of the technique in its modern form.
- Cenedese — the Cenedese glasshouse produced sommerso work of considerable quality in the 1950s and 1960s, often in bold, sculptural forms with strong colour contrasts.
- Barovier & Toso — one of the oldest Murano glasshouses, Barovier & Toso produced sommerso work alongside their other decorative traditions throughout the mid-century period.
Scandinavia: The Northern Tradition
Parallel to the Murano tradition, and in some respects influenced by it, a distinct sommerso tradition developed in the Scandinavian glasshouses of Sweden and Finland in the mid-20th century. The Scandinavian approach to sommerso reflects the broader aesthetic values of Scandinavian design — restraint, functionalism, and a deep engagement with natural forms and materials — and produces work that is in many ways the complement of the more exuberant Italian tradition.
Where Murano sommerso tends toward bold colour, organic asymmetry, and sculptural drama, Scandinavian sommerso is typically more restrained in colour, more geometric in form, and more concerned with the relationship between the glass object and its functional context. The finest Scandinavian sommerso pieces have a quiet, meditative quality — the colour seems to breathe within the glass rather than shout — that is entirely characteristic of the tradition.
Orrefors
Orrefors, founded in 1898 in Småland, Sweden, is the most internationally celebrated of the Scandinavian glasshouses and the one most closely associated with the development of artistic glass design in the 20th century. The glasshouse's reputation was established in the 1910s and 1920s through the work of two designers whose influence on Scandinavian glass was transformative: Simon Gate and Edward Hald.
Edward Hald (1883–1980) was one of the most significant figures in 20th-century Scandinavian design. Trained as a painter — he studied briefly under Henri Matisse in Paris — Hald joined Orrefors in 1917 and remained associated with the glasshouse for the rest of his long career. His work at Orrefors encompasses a wide range of techniques and styles, from the elaborate engraved Graal glass of the 1920s to the cleaner, more modernist forms of the post-war period.
Hald's contribution to the sommerso tradition at Orrefors was primarily through his development of the Ariel technique — a variant of sommerso in which air bubbles are trapped between the colour layers in controlled patterns, producing a design of extraordinary delicacy suspended within the glass. Ariel glass, developed at Orrefors in the late 1930s, is one of the most technically demanding and visually spectacular of all glass techniques, and the finest Ariel pieces by Hald and his colleagues are among the most valuable objects in the Scandinavian glass market.
Vicke Lindstrand
Vicke Lindstrand (1904–1983) is one of the most versatile and prolific designers in the history of Scandinavian glass. He worked at Orrefors from 1928 to 1940, where he developed the Ariel technique alongside Edward Hald and made significant contributions to the glasshouse's engraved and sommerso traditions. His Orrefors work is characterised by its figurative quality — Lindstrand was a gifted draughtsman — and by the boldness of his colour and form.
In 1950, Lindstrand joined Kosta — the other great Swedish glasshouse — as artistic director, a position he held until 1973. His work at Kosta represents the full flowering of his mature style: bold, sculptural forms in sommerso glass with strong colour contrasts, often incorporating engraved or cut decoration that reveals the colour layers in section. Lindstrand's Kosta pieces are among the most actively collected objects in the Scandinavian glass market, and his work spans an enormous range — from small, intimate vases to large sculptural pieces of considerable ambition.
Key characteristics of Lindstrand's work include his use of controlled asymmetry — forms that appear organic and spontaneous but are in fact precisely calculated — and his mastery of the relationship between colour and form. His sommerso pieces at Kosta often use a single strong inner colour — deep blue, green, or amber — within a clear outer layer, allowing the form of the vessel to modulate the apparent colour as the viewing angle changes.
Olle Brozén
Olle Brozén (1916–1987) worked at Kosta from 1953 to 1957 and subsequently at Flygsfors, where he developed a distinctive approach to sommerso that is immediately recognisable to the experienced collector. Brozén's sommerso pieces — produced under the Coquille series name at Flygsfors — are characterised by their use of multiple colour layers in unexpected combinations, their organic, often asymmetric forms, and the extraordinary luminosity of their colour.
The Coquille series, produced from 1952 onwards, represents Brozén's most celebrated work. These pieces — typically vases and bowls in sommerso glass with two or three colour layers — have a warmth and immediacy that distinguishes them from the more austere work of some of his contemporaries. The colour combinations Brozén favoured — amber and green, pink and clear, blue and amber — have a natural, almost geological quality, as if the glass had formed itself rather than been made.
Brozén's work is signed on the base — typically with his name and the Flygsfors mark — and is therefore more straightforwardly attributable than much Murano sommerso. Signed Coquille pieces in good condition are actively sought by collectors of Scandinavian glass and command prices that reflect their quality and rarity.
Kosta and the Broader Scandinavian Tradition
Kosta, founded in 1742 and one of the oldest continuously operating glasshouses in the world, was the other great centre of Swedish artistic glass alongside Orrefors. Under the artistic direction of Lindstrand and, later, Mona Morales-Schildt and Bertil Vallien, Kosta produced sommerso work of the highest quality throughout the mid-century period.
Other significant Scandinavian glasshouses working in the sommerso tradition include Flygsfors (where Brozén worked), Ekenas, and the Finnish glasshouse Iittala, where designers including Tapio Wirkkala and Timo Sarpaneva produced work that, while not always strictly sommerso in technique, shares the same engagement with colour, form, and the inherent properties of glass as a material.
Collecting Sommerso Glass: What to Look For
Quality of the Layers
The primary criterion for assessing the quality of a sommerso piece is the precision and consistency of the colour layers. In the finest pieces, each layer is of even thickness throughout the vessel, the boundaries between layers are sharp and clean, and the colour of each layer is consistent and free of streaks or variations. Uneven layers, blurred boundaries, or colour inconsistency indicate lower quality work.
Form
The relationship between the form of the vessel and its colour layers is fundamental to the aesthetic success of a sommerso piece. In the finest examples, the form is designed to express the colour — the curves and angles of the vessel modulate the apparent depth and intensity of the submerged colour as the viewing angle changes, creating a dynamic visual experience. A form that does not engage with its colour layers is a lesser piece regardless of the technical quality of the layering.
Colour
The colour of sommerso glass is one of its primary attractions, and the finest pieces use colour with great sophistication. Strong, saturated colours — deep amber, rich blue, intense green — are generally more desirable than pale or washed-out colours. Unusual or unexpected colour combinations — the hallmark of the most adventurous designers — command premiums over more conventional choices.
Attribution and Signatures
Scandinavian sommerso is generally better documented than Murano sommerso, and many pieces are signed or labelled with the glasshouse name and designer. Signed pieces by named designers — Lindstrand, Brozén, Hald — command significant premiums over unsigned or unattributed examples. Murano sommerso is more complex to attribute, and the collector should seek specialist advice before paying a premium for a specific attribution.
Condition
Sommerso glass is relatively robust — the thick walls of most pieces provide good protection against minor knocks — but chips, cracks, and scratches to the outer surface are common and significantly affect value. Examine the rim, foot, and body carefully under good light. Internal bubbles or inclusions that are not part of the design may indicate production flaws rather than deliberate decoration.
The Market for Sommerso Glass
The market for mid-century sommerso glass has grown significantly over the past two decades, driven by the broader revival of interest in mid-century design. The finest pieces by the most celebrated designers — Poli for Seguso, Lindstrand for Kosta, Brozén for Flygsfors — now command prices that reflect their status as significant works of 20th-century design:
- Flavio Poli for Seguso — major pieces from the Valva and Corroso series can command £5,000–20,000 or more at specialist auction; smaller or less significant pieces from £1,000–5,000.
- Vicke Lindstrand for Kosta — signed pieces range from £500–5,000 depending on size, form, and colour; exceptional pieces can exceed these figures.
- Olle Brozén Coquille for Flygsfors — signed pieces typically range from £300–2,000; the most desirable colour combinations and forms command the higher end.
- Edward Hald Ariel for Orrefors — Ariel pieces are among the most valuable Scandinavian glass objects; significant examples can command £5,000–20,000 or more.
The broader market for unsigned or less attributed Murano and Scandinavian sommerso offers very accessible entry points — attractive pieces of genuine mid-century production can be found for £100–500 — making this one of the more democratic collecting fields in the decorative arts.
The Wonder Room occasionally offers mid-century decorative glass including sommerso pieces from Murano and Scandinavian makers. Explore our current collection or browse further guides in Collector's Insights.