Air-bubbles are a common side effect of material fabrication across a range of mediums. Air-bubbles occur within the material aggregate when: adding plaster powder to water; pouring a catalyzing agent into liquid resin; coating a surface with a light sensitive emulsion in wet plate collodion; couching paper pulp. Some of these air bubbles are microscopic, some are the size of a pea, but all are considered a nuisance to the structural integrity and aesthetic harmony of the artwork. The pockets of air that get trapped when shaping materials in their fluid state or mixing their constituting ingredients become in the final art object: an unwanted texture interrupting the smooth surface of the set plaster; an internal gap in the otherwise solid resin block; a distortion in the image registered upon the light-sensitive emulsion; an inadvertent watermark on the dry sheet of paper. Though a persistent element of artistic fabrication, air-bubbles are largely left out of the story of how an artwork was created. Air-bubbles are seen as a defect, an accidental occurrence to be remedied through vibrating tools, degassing vacuums and technical gestures like wedging and tapping. Additionally, air-bubble removal leaves no trace, neither on the art object nor in the studio. Unlike physical material detritus—plaster chips, water rings, or concrete dust—their removal just releases invisible gases into the air. An artist’s tools and movements are often registered in the worked substance, but air-bubble removal is imperceptible in the finished artwork, like an invisible material.
Though the presence of air-bubbles is seen as bad craft, certain glass techniques intentionally trap air-bubbles, like pulegoso, bullicante and pâte de verre. Pâte de verre consists of a mixture of crushed glass, a binding agent, and water (hence, ‘paste’) that is layered in a refractory mold and fuses when kiln fired. Its defining quality is the powdery consistency of the crushed glass. While most kiln casting utilizes fragments of fusible glass (frit), pâte de verre uses finely ground frit. This frit traps many small bubbles, and each increases the opacity of the glass because each sphere of gas refracts light rather than letting light pass through linearly.
Historically, practitioners have been interested in pâte de verre because of its ability to hold color, its chromatic precision. Air-bubbles—usually seen as a material defect—become, with pâte de verre, an intentionally sought and manipulated characteristic of glass casting. Air-bubbles, a negative form and the absence of material, paradoxically produce opacity in transparent glass. Focusing on nineteenth-century France, and the reinvention of pâte de verre by Henry Cros, this paper reframes the history of opaque bubbly glass as the compound of two ‘invisible’ materials—transparent glass and air-bubbles. This analysis of pâte de verre illuminates that which cannot be seen in the finished artwork: the invisible labor and gestures of material creation, the invisible accidents of fabrication, and the invisible history of air-bubbles in art making.
Key-words: pâte de verre, glass, air-bubbles, casting
Belfort, Anne-Marie. “Pates de Verre d’Henry Cros (1840-1907).” Cahiers de La Céramoque Du Verre et Des Arts Du Feu, no. 39 (1967).
Duret-Robert, François. “Le Sculpteur Qui a Redécouvert La Pâte de Verre: Henri Cros.” Connaissance Des Art, no. 274 (December 1974).
Frantz, Susanne K., and Jean-Luc Olivié. Particle Theories: International Pâte de Verre and Other Cast Glass Granulations. New Jersey, USA: Museum of American Glass at Wheaton Village, 2005.
Hollister, Paul. “Pâte de Verre: The French Connection.” American Craft 48, no. 4 (September 1988): 40–47.
Olivié, Jean-Luc. “Un Atelier et Des Recherches Subventionnés Par l’Etat: Henry Cros à Sèvres.” In Rencontres de l’École Du Louvre-La Sculpture Du XIXe Siècle, Une Mémoire Retrouvée. Les Fondes de Sculpture. Paris: La Documentation française, 1986.
Stewart, Max, and Tone Ørvik. Pâte de Verre: The Material of Time. Pennsylvania: Schiffer Publishing, 2022.
Testard, Maurice. “Henry Cros.” L’Art Décoratif, 1908.
Tisserand, Ernest. “Chronique de L’Art Décoratif: La Pate De Verre.” L’Art Vivant, January 1, 1929.
Emily Madrigal
Art History PhD student
University of Virginia
https://www.emilymadrigal.com/cv
Air-bubbles are a common side effect of fluid material fabrication—mixing plaster, coating wet plate collodion, couching paper pulp. They are seen as a defect, an accidental occurrence to be remedied through vibrating tools, degassing vacuums and technical gestures like wedging and tapping. However, certain glass techniques, like pâte de verre, intentionally trap air-bubbles for opacity and chromatic precision. Henry Cros reinvented glass paste in nineteenth-century France. This paper reframes pâte de verre as the compound of two ‘invisible’ materials—transparent glass and air-bubbles. Additionally, this analysis illuminates that which cannot be seen in the finished artwork: the invisible labor, gestures, and accidents of fabrication.