A wooden structure attached to the reverse of a panel painting, which, in theory, is designed to prevent warping or splitting of the support with changes in humidity.

The concept of cradling may have developed from the practice of early Italian panelmakers of placing wooden supporting battens in shallow channeled grooves on the reverse of panels, running perpendicularly to the grain of the wood. The modern cradle, which was developed during the nineteenth century, is a more complex assembly of interlocking supports: strips of wood running parallel to the grain are glued to the panel in a fixed position; wooden strips aligned perpendicularly to the grain are held in place by the fixed bars but are free to move with the natural expansion and contraction of the panel as it responds to changes in temperature and humidity. Prior to application of a cradle, the reverse of the original panel is often planed to create an even surface.

Unfortunately, cradles can become locked in place over time as the strips of wood in the cradle expand and may actually promote the kinds of problems (such as splits) that they were designed to prevent. The massive nature of many cradles can also significantly alter the basic character of a painting: if the original panel is thinned to an excessive degree, the impression of the cradle can be transferred to the surface of the painting, creating an unsightly washboard effect. Since cradles can cause damage, today they are often removed from panel paintings.

In recent years, cradling has fallen out of use in favor of less invasive techniques for treating structural problems in wooden supports.

Source: Looking at Paintings: A Guide to Technical Terms / eds. Tiarna Doherty and Anne T Woollett. (Los Angeles: J. Paul Getty Museum, 2009), p. 22.