The art of suspended colour in twentieth-century Murano glass
Few techniques are as closely associated with twentieth-century Murano glass as sommerso.
Deep violet surrounded by blue. Ruby suspended inside amber. Dense colour apparently floating within a perfectly clear outer layer. Sommerso glass has a remarkable ability to make colour appear almost three-dimensional.
The technique became particularly celebrated in the 1950s through the work of Flavio Poli for Seguso Vetri d’Arte, whose sculptural vessels helped define the image of post-war Murano glass internationally. But one distinction is essential from the outset:
Sommerso is a technique, not a maker.
A piece of glass can be genuine Murano sommerso without being designed by Flavio Poli - and the presence of several colours alone is not enough to attribute an object to either Poli or a particular Murano glasshouse.
Understanding sommerso begins with the glass itself.
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What is sommerso glass?
The Italian word sommerso means “submerged.”
In glassmaking, the term refers to a technique in which layers of differently coloured transparent glass are superimposed, creating the appearance of one colour being suspended inside another.
The Museo del Vetro in Murano describes vetro sommerso as glass composed of several overlapping transparent layers. Museo del Vetro
Unlike painted or applied decoration, the colour is therefore inside the body of the object.
A coloured mass of hot glass can be enclosed within another layer, often followed by a final casing of clear glass. More than two colours may be combined, producing increasingly complex effects.
Once shaped, the thickness and geometry of the finished piece alter the way these internal layers appear. Looking directly through a vase may reveal one colour combination; looking through a thick polished edge can produce something entirely different.
This relationship between colour, depth and optical distortion is fundamental to sommerso.
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Colour as part of the form
Sommerso is particularly effective in heavy, sculptural glass.
As the layers become thicker, light has to travel through greater volumes of differently coloured material. Colours overlap optically, edges become more intense and the transparent outer layer can act almost like a lens.
For this reason, the silhouette of a sommerso piece is not simply a container for decoration.
The shape actually determines how the colours are seen.
Many of the finest twentieth-century examples therefore combine comparatively restrained forms with substantial amounts of glass. Cutting, grinding and hand polishing could further transform the object after it had left the furnace.
This painstaking cold-working was especially important in some of the celebrated designs produced by Seguso Vetri d’Arte during the 1950s. Christie's describes several of Flavio Poli's sommerso series as requiring elaborate cutting and polishing, giving the finished pieces a sculptural character that went far beyond ordinary blown glass. Christie's
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Flavio Poli and Seguso Vetri d’Arte
No history of sommerso would be complete without Flavio Poli.
Born in Chioggia in 1900, Poli began designing glass in the late 1920s. In 1934 he joined the Murano company then known as Barovier Seguso Ferro. In 1937, after Poli became a partner, the firm adopted the name Seguso Vetri d’Arte. Museo del Vetro
Under Poli's artistic direction, Seguso became one of the most important protagonists of modern Murano glass.
By the post-war period, Poli was exploring the possibilities of heavy glass and layered colour with extraordinary sophistication. His sommerso vessels of the 1950s combined rich colour with simple, almost monumental forms.
The Museo del Vetro records combinations including steel grey with violet, green with Chinese red and yellow, and light ruby with resin yellow. These thick superimposed layers produced colours that changed according to the depth and angle through which they were viewed. Museo del Vetro
The result was distinctly modern: decorative glass that approached sculpture.
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The 1954 Compasso d’Oro
The importance of Poli's work was recognised beyond Murano.
In 1954, at the first edition of the Compasso d’Oro - one of Italy's most important design awards - a large blue, ruby and clear sommerso vase designed by Poli for Seguso Vetri d’Arte received the award. Museo del Vetro
The same period also saw his work entering major museum collections.
The Museum of Modern Art in New York holds a 1954 glass vase by Flavio Poli manufactured by Seguso in Murano. The Museum of Modern Art
This international recognition helped establish Poli's sommerso designs as some of the defining objects of post-war Italian glass.
And perhaps inevitably, his name became closely associated with the technique itself.
But not every sommerso is Flavio Poli
This is where careful attribution becomes important.
Flavio Poli did not make every sommerso object. Nor was sommerso exclusive to Seguso Vetri d’Arte.
Poli was one of the technique's most influential twentieth-century interpreters, but the success of his work encouraged its much wider use.
Christie's specifically notes that, following the success of Poli's designs, the sommerso technique was adopted by numerous Murano glassworks. Christie's
This means that a genuine Murano sommerso piece may have no connection whatsoever to Flavio Poli.
The distinction is fundamental:
Sommerso describes the technique. Flavio Poli is one of its great interpreters — not its only author.
Attributing every attractive piece of layered Murano glass to Poli removes precisely the complexity that makes twentieth-century Murano production so interesting.
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Murano itself was never one aesthetic
It is also useful to remember that twentieth-century Murano was not a single workshop or a single visual language.
Different furnaces experimented simultaneously with very different techniques and ideas.
The Museo del Vetro describes the extraordinary variety of post-war Murano production: Flavio Poli's submerged glass for Seguso, Giulio Radi's polychrome glass for AVEM, Venini's use of techniques such as incalmo, filigree and murrine, and Archimede Seguso's experiments with filigree. Museo del Vetro
The term Murano therefore tells us where a tradition of production developed; it does not identify an individual designer.
Likewise, sommerso identifies a technique; it does not identify an author.
Those two distinctions are particularly important when studying unsigned glass.
Not every multicoloured glass object is sommerso
Another common confusion concerns the technique itself.
Several colours appearing in the same object do not automatically make that object sommerso.
Murano glassmakers developed an immense technical vocabulary during the twentieth century. Colour could be introduced through murrine, filigree, incalmo, applied elements, internally decorated glass and numerous other processes. Museo del Vetro
With sommerso, what matters is the structural layering of the glass.
The colours belong to separate masses of glass enclosed one within another.
When the object is viewed through its edge or its thickest sections, those layers often become particularly legible.
That internal construction — rather than simply the number of colours present — is what defines the technique.
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From technique to attribution
Recognising sommerso and identifying who made a particular object are two separate stages.
A documented Flavio Poli attribution may be supported by a known model, archival documentation, period literature, original labels, signatures or strong provenance.
For example, Christie's has documented a 1954 Poli vase for Seguso retaining its Seguso label and model number, while another important 1954 model can be connected directly with specialist literature and provenance. Christie's
These details matter.
Without them, visual similarity should be treated cautiously.
A piece can still be beautiful, authentic and historically interesting without attaching a celebrated designer's name to it.
In decorative arts, a careful attribution is more valuable than a famous attribution.
A piece from Les Trois Curieuses
Our Murano Sommerso Glass Ashtray offers a particularly striking example of the visual qualities that make the technique so compelling.
Dating from approximately the 1960s, the substantial free-form piece combines purple, blue and clear glass.
The colours appear embedded within the object rather than applied to its surface. Viewed from above, they create a bold graphic composition; seen through the thick sides, the coloured layers overlap and distort one another.
It is precisely this change of perception as the object is turned that gives sommerso its extraordinary depth.
Rather than attributing the piece automatically to a well-known designer, we prefer to describe what the object itself allows us to establish: a vintage Murano sommerso piece, displaying the layered colour construction characteristic of the technique.
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Why sommerso still feels modern
More than half a century later, sommerso glass retains a remarkably contemporary quality.
Its appeal comes from something deceptively simple: colour is not placed on the object — colour becomes part of its volume.
That idea allowed designers such as Flavio Poli to create some of the masterpieces of post-war Murano glass. But it also became part of a much broader vocabulary used across Murano's furnaces and workshops.
And that broader history is important.
Not every sommerso is Flavio Poli.
Not every multicoloured Murano glass is sommerso.
And technique alone is never enough to identify a maker.
The most interesting objects begin when we separate those questions — and allow the glass, its construction and its documentation to tell us what can genuinely be known.
