Professional paper
https://doi.org/10.17018/portal.2019.12
Systems for Ensuring Permanent Tension of Canvas Paintings
Slobodan Radić
; Croatian Conservation Institute, Department for Easel Painting, Zagreb, Croatia
Abstract
In the mid-15th century, oil paintings began to be painted on canvas, so the development of the stretcher followed the use of canvas as a carrier. The first stretching on the stretcher bars is performed together with setting up the canvas through impregnation and preparation, and cannot be corrected. If paintings stretched on a fixed stretcher are exposed to adverse microclimatic conditions, the forces of the material resist each other, which often leads to deformation and damage to the paintings, as well as excessive loss of tension on the stretcher. The situation is often exacerbated by the decay of the wooden frame, often at the same time as the loss of elasticity of the canvas. Throughout history, various stretchers have been created, from the simplest to those with keys. In the late 18th century, expansion-bolt stretchers came to be used in order to resolve the issue of continuous stretching of paintings. Excessive and constant tension in the corners leads to the same effect as in fixed stretchers: that is, stress is concentrated in the corners, leading to various damage to the canvas. Stretchers were considered to perform two functions: mechanical support and provision of tension for the painting. In reality, due to its structure, the stretcher is only able to properly perform mechanical support of the canvas. In the early 1950s, Roberto Carità separated mechanical support and tension of the canvas, which had previously been left to the stretcher. He devised the method of elastic tension for canvases at the Istituto Superiore per la Conservazione ed il Restauro, in Rome, which sparked a real revolution. With this method, and using different elastic springs and regulating their force, we get elastic tensioning that allows equal continuous tension of the canvas in all directions, regardless of the mechanical support exerted by the stretcher. Gustav Berger also worked on this system, as did many Italian restorers who systematically conducted research, the most prominent being Antonio Iaccarino Idelson. In Croatia, this system was first used in 1957 at the Conservation Institute in Zadar. At the end of the 1980s, the practice was adopted at the Institute for Restoration of Works of Art, in Zagreb, and has been continuously used ever since. Over twenty paintings, mostly with large-format canvases, have been stretched using this method. The method of constructing the stretcher and the tensioning is adapted to each painting, depending on its state of preservation, dimensions, shape and conditions of accommodation. The paper describes two examples of tensioning in more detail.
Keywords
large format; stretcher; elastic tension; springs; microclimatic conditions
Hrčak ID:
231918
URI
Publication date:
31.12.2019.
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