Italian Art: Venetian Plaster

Visit Italian Frescoes for more pictures of the paintings and procedures

Venetian Plaster

Venetian plaster, or Venetian stucco, has been used for centuries around the world, in homes and offices, on architectural masterpieces and in everyday buildings. Architects and interior designers, home-owners and artists, all have marveled at the distinctive beauty of this highly popular form of wall surfacing, and throughout the ages the artisans who were skilled at creating such beauty have been revered and sought after.

It is distinctive, subtly graduated in color, and can have a rough finish although traditionally it is shiny and many-layered. This shiny surface draws the touch, as though one’s fingers would not stop at the surface itself but sink into it as easily as into a pool of cool water.

Venetian Plaster History

The origins of Venetian plaster lie hundreds of years ago, relatively hidden in the past with some sources claiming that its ancient predecessor was developed 9000 years ago in Mesopotamia – now Syria, Iraq and Iran. Certainly a form of plastering was in use there, crude and rough though it was. Other countries and other ages used similar and more and more developed plastering techniques: tombs in Egypt were covered with a lime and gypsum plaster; entire cities in India were plastered – one in particular used blood as a pigment, resulting in its nickname The Pink City; China used plaster extensively to cover rough stone walls. And the list goes on. From the Middle East to India, from Egypt to China, to Greece and on to the ancient Roman Empire, plaster of some kind was used almost everywhere in the ancient world.

And in Pompeii, particularly, plastering as an art form was developed quite extensively, resulting in walls throughout the city filled with spectacular frescoes and colorful scenes from myth, history and fancy.

But Venetian plaster is different than other types in its multi-layers and highly polished surface. Unlike frescoes, it is smooth surfaced, often tinted with pigment but not generally covered with images or bright colors. Its uniqueness lies in large part with the processes and ingredients that have remained essentially the same since the first century AD.

From the first century AD, techniques and processes remained much the same. While always in use, it was rediscovered and made popular again in the Italian Renaissance. Artists and architects embraced it as both an old and new technique, and Venetian plaster became a highly desired finish for walls both interior and exterior.

Significant changes in the processes and materials didn’t occur until the mid 1900s when Carlo Scarpa, an Italian architect, began using glues and acrylic resins, and others changed the process in other ways, taking it from seven layers to three… but to understand the changes one must first know how Venetian plaster has been made through time.

The Materials

Creating a finish of Venetian plaster is quite an involved process. It takes time, patience, an eye for detail, and relatively precise ratios of materials. These have included limestone, gypsum, malt, beer, eggs, animal hair, blood, other pigments, sand, marble dust, lime, and more recently acrylics and fiberglass.

We don’t know the exact moment what we would call Venetian plaster by today’s definition was first used, but we can certainly discuss how it has varied and changed since that unknown moment. Essentially the base has stayed the same – limestone, with a stone or marble powder for later layers – but the specifics have varied depending on geography, culture, technological development, and basic human innovation.

Let’s start in the fourth century BC when the Romans discovered that limestone, when mixed with silica, alumina or other volcanic material, would set and harden under all kinds of conditions, even under water. In other developments, they kept limestone in pits and dark cellars for three years to allow it to mature, and realized that exposing the limestone plaster to the atmosphere before applying it to walls allowed it to absorb atmospheric gases. This neutralized its caustic nature, allowing for more ease of use.

It was at this same time that animal hair was used to reinforce the plasters, and beer, malt and eggs assisted in its plasticity.

And around the world, plaster wherever it was applied looked similar – while possibly smooth, it wasn’t yet what we know today as Venetian plaster.

A new finish was developed in the fifteenth century that resembled marble but was much lighter. Called Marmorino, it was used primarily on the surfaces of buildings in Venice where it was necessary to keep them as light as possible. Revived in the sixteenth century by Palladio, Marmorino was used extensively in the Veneto region of Italy.

In other European countries, gypsum, animal glue, pigments and sometimes sand, marble dust and lime, were used to imitate marble and added beauty to already spectacular buildings. The most recent innovation to the process involves the additions of glues and acrylics.

And all of these changes have gone hand in hand with the changes in the actual application process.

The Process

Vitruvius, a first century BC Roman engineer and architect, described a seven-step process. The first few layers applied to a wall, made of ground limestone, were to smooth and level the rough underlying masonry; subsequent layers included a fine marble dust. The limestone base was later replaced with hide glues and more recently with acrylic resins, and the process shortened from seven layers to three.

Regardless of materials or number of layers, each layer was smoothed on using varying techniques, and let dry. The wall was then sanded and another layer added; a third and possibly fourth (fifth, sixth and seventh) layer were added, each sanded in turn. And the final layer was burnished with specialized tools – today a trowel – to a highly reflective sheen.

This sheen is what gives Venetian plaster its fame, and is the result most sought after by those seeking to create an old-world look in their homes or other spaces.

Venetian Plaster Today

Many companies today offer Venetian plaster finishes for your walls. They can be found rampant on the Internet, and all boast of the natural look and feel of their products, especially those who use artificial materials and shortened processes.

The debate rages between purists and those who espouse using today’s innovations. As a result, it is impossible to talk about a typical contemporary process, or typical materials in use. The only consistency is that all good artisans can create a work of art – a surface that is as deep and luminescent as a pearl, offering views of both the world in which we live, and the world of the ancient past.

Visit Italian Frescoes for more pictures of the paintings and procedures

By Teresa Cutler

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