Full-Fire Reduction Faience Marcia Selsor

Appears in the Jul/Aug 2016 issue of Pottery Making Illustrated.

Faenza has long been a majolica center in Italy. The long history of majolica, i.e. tin-glazed earthenware, goes back to 10th-century Persian kings seeking ceramics as white as Chinese porcelain of the time. Persian chemists of the court developed an opaque tin glaze to cover the local earthenware clays. As Islam spread from the Middle East across North Africa and into Spain, the ceramic process of tin glaze and the commonly added luster decoration followed into the new lands of the Islamic culture. Majolica could be found across North Africa and in Spain, Portugal, France, and into Italy by the 12th century. Italy had several majolica centers: Pisa, Deruta, Urbino, Faenza, Gubbio, Montelupo, Siena, Florence and many more. Today, Deruta, Florence, Gubbio, Montelupo, and Faenza still produce a large volume of majolica. And since the early Renaissance the word for the Italian tin-glazed ware became known as faience (from Faenza) rather than majolica.

Bottega Vignoli

Among the most popular ceramic studios in Faenza is the Bottega Vignoli, where full-fire reduction faience—a technique first used by the Persians, dating back to the 11th century—has been produced for over 30 years. It’s one of the few places still practicing the technique in Italy. Saura and Ivana Vignoli both decorate the ware along with assistants. Their work is tin-glazed earthenware decorated with metallic oxides, which are reduced as the kiln is in the down firing cycle after the glaze reaches maturity. The result is a shimmering metallic surface resembling luster (1, 2).

Inspired by the Surrounding History

When I was in the 6th-century-era Basilica of San Vitale, I noticed the fish above a figure of Christ high up in the nave. The red and blue sardines immediately reminded me of the Vignoli tin-glazed reduction ware. I asked Saura if she was influenced by the mosaics in San Vitale. She was delighted and her response was, “Of course! The Byzantine mosaics of fish in Ravenna are one of our principal inspirations for decoration. The imagery of ancient mosaics along with the surface quality of the Renaissance majolicas of Faenza all have an impact on our adopted Persian and Mediterranean style (3a–3c).”

Decorating Process

Pieces are decorated after the tin glaze has been applied and allowed to dry for several days. Saura first marks off the geometric design in pencil on the hardened surface of the tin glaze (4). Next, she starts painting the outline of the sketch with a dark slip to reinforce the pattern (5). Then she introduces the arched pattern over the concentric circles (6). Metallic oxides are added after the complete design is laid out (7, 8).

Firing Effects

To achieve the metallic luster quality Bottega Vignoli is known for, the pieces are first bisque fired to 2120°F (1160°C), or cone 2. The pieces are glazed and decorated, then a lower temperature glaze firing occurs at 1688°F (920°C). The glaze firing lasts 24 hours. Bottega Vignoli uses an indoor, front loading electric kiln for both firings (9). The kiln is fitted with a venting tube that leads an to external aspiration cap to eliminate the fumes.

During the later part of the firing, as the kiln temperature is dropped to 1112–1212°F (600–650°C), it’s put into reduction by introducing 35 ounces (1 kilogram) of sugar combined with 2 cups ( liter) of denatured alcohol (10), for every 17 cubic feet (0.5 cubic meter) of interior kiln area. Saura notes that the thickness of work and the density of the kiln load may influence this proportion. The mixture is only added once during the firing.

Saura uses a heavy piece of three-sided, steel angle iron (11), to introduce the mixture (12) through a small door near the bottom of the kiln (13).

At this temperature, the glaze has hardened and the metal oxides on top of the glaze react to this reduced atmosphere. The combustion of the mixture chokes off the oxygen in the kiln and the metallic oxides react by developing into reflective metallic surfaces and occasionally some with transparent effects.

The Bottega Vignoli considers this process to be their signature style, which they have produced for 40 years. Their work has won many awards over the years, has been shown in exhibitions worldwide, and is widely sought after by private and corporate collections. Saura notes that her technique may be adapted to different materials and temperatures, as she has done it successfully when teaching in studios other than her own. The process is still an experiment for her in every firing, to her, this is the true nature of the ceramic artist.

To see more by Bottega Vignoli, check out https://artemest.com/artisans/bottega-vignoli.

Translation help courtesy of Claudia Bruhin, Director of La Meridiana International School of Ceramics in Tuscany, Italy, www.lameridiana.fi.it.

Images 1, 4, 6, 8, and 10 courtesy of CS Lim. Images 3c, 9, and 11 courtesy of Cecilia Cunningham. Images 3b, 7, and 12 courtesy of Cheryl Weinstein. All other images courtesy of the author.

Marcia Selsor is a Professor Emerita from Montana State University-Billings. She teaches workshops in the US, Canada, and Europe and serves on the Advisory Board of the Potters Council.

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