Stretchers and Strainers: Introduction
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Author: Kennis K. Kim
Date: Submitted September 2000
Compiler: Barbara A. Buckley
The primary support of a painting's structure may be anything from an aluminum panel to vellum, including wood, fabric, and paper. For the purpose of this chapter, primary support will refer to flexible supports, usually meaning a woven textile and generically referred to as canvas.1 An auxiliary support is the secondary structure of the painting that supports the textile. Paintings on textile supports require an auxiliary support to reduce the movement of the textile. Auxiliary supports can be quite varied in material, structure, and form. This chapter will examine the use of stretchers and strainers as auxiliary supports.
A strainer is an auxiliary support that has its corners fixed with hardware, such as nails or screws, dowels or splines, or with an adhesive such as carpenter's glue. Strainers, because of their fixed corners, cannot be expanded, resulting in a slackening of the canvas support through exposure to environmental fluctuations and deterioration of the textile fibers. When a painting becomes slack on a strainer, the painting is frequently removed from the original strainer and transferred to a new auxiliary support, usually a stretcher. Since paintings are often removed from their original strainers due to slackness or because of deterioration of the strainer, there are very few examples from the 18th century or earlier. Evidence of early strainer use is limited to a “trompe-l'oeil” by Cornelis Gysbrechts (Copenhagen), dating from c. 1660 with dowel joined corners (Marijnissen 1985), a Copley painting from the late 1700s with mortise and pin joined corners (Katlan 1992), and some written descriptions.
A stretcher is an expandable auxiliary support. Early painting on canvas, as depicted in paintings by the Dutch School artists Codde, Molenaar, and Rembrandt, utilized “working” or temporary stretchers in the studio (Marijnissen 1985).2 The canvas support was laced to the working stretcher, leaving a small space between the edge of the canvas and the interior edge of the stretcher; after completion, the painting was transferred to a final auxiliary support. The practice of attaching the canvas to the stretcher prior to painting dates to the 18th century. Keys—small wooden wedges inserted into the interior corners of the stretchers for expansion purposes—were also introduced during the 18th century. Since the United States Patent Office was founded in 1793, thousands of patents have been issued for stretcher design and the production machinery.
Stretchers and strainers are the foundation of a painting's structure. A thorough examination of a stretcher or strainer can serve as a valuable means of understanding the technique of the artist, determining if the painting has undergone previous conservation or restoration treatments or if the painting was cut from a larger work. An original stretcher or strainer can also establish the date of the painting. Stretchers and strainers are often made of wood that deteriorates with age; this, in combination with a painting's need for additional support as it ages and grows structurally weaker, has resulted in the loss of many original auxiliary supports and the information that they carry.
Today, heavy-duty, custom-built stretchers and strainers are available to both conservators and artists. These stretchers may be constructed from wood, plastics, metal, or a combination of these materials. The methods of expansion, corner joints, and bevel or angle of the face of the bars may all be chosen with the best interest of the work of art in mind.
- Katlan, Alexander W. 1992. American artists' materials, Vol. II. A guide to stretchers, panels, millboards, and stencil marks. Madison, CT: Sound View Press.
- Marijnissen, R. H. 1985. Paintings: Genuine, fraud, fake. Modern methods of examining paintings. Zaventem, Brussels: Elsevier Librico.
ADDITIONAL RESOURCES CONSULTED
- Gettens, R. J., and G. L. Stout. 1966. Painting materials: A short encyclopedia. New York: Dover Publications, Inc.
- 1 There are numerous alternatives to woven textiles for primary supports, especially in contemporary art (20th/21st century).
- 2 It is thought that these were actually nonexpandable strainers.