In easel painting as much as in mural painting, the supporting material is decisive for the final appearance of the painted work of art.
The choice materials for easel painting have evolved very slowly. The natural wood panel, traditionally square, was either hewn out of a single plank or – to gain more width – assembled with roughly identical planks; wood being the most readily available universal material in pre-industrial times. However, using massive natural wood is in many ways inconvenient.
Cut wood, i.e. wood that no longer makes part of a living tree, has inevitably internal tensions. Wood fibres and cellular mass develop under constant stress. The cellular structure counters and stabilizes unequal growth coming from the bends, twist and turns necessary to keep weight above ground and the tree in equilibrium. When wood is cut into planks, the inside tension, freed from all balancing forces, makes planks warp and bend. Furthermore, wood absorbs and dissolves humidity with considerable structural changes. Keeping the manufactured panel in too humid or too dry conditions, or alternating storage in humid and dry atmospheres, inevitably makes the wood “work” and weakens adherence of applied paint. This is prone to happen with the singular plank painting and is inevitable with the assembly. An assembled panel is a set of unruly elements.
In spite of these shortcomings, the panel gave the perfect support to the smooth-surfaced and multilayered oil painting technique as developed by Van Eyck in the 15th century. His remarkable manner gave to the paintings of his day a never before seen transparency and this feat would have been impossible without the stiff panel underground.
The stretched linen canvas was easier to manufacture and lighter to handle; the linen being stretched onto a thin wooden frame. The design of the stretcher developed continuously over the years to improve maintenance of tension and to lessen deteriorating effects produced on the stretched material (breaking edges). As with all natural materials, linen is subject to tensions and reactions that are spread unequally over the surface and that result in bulging, slackening or tear.
After the First World War the modern board developed, made out of wooden ply, fibres or particles. The great advantage with board was its physical inertia, a direct result of its artificial manufacture. This produced relative insensitivity to structural tension.
The use of linen canvas as support for easel painting has remained well into our days, be it for traditional reasons. However, the aspect of any painted surface varies depending on the combination of painting technique and supporting structure. Canvasses that are laid on board tend to lose much of their initial surface characteristics and the aesthetic result is often unsatisfactory.
There was a natural evolution in the oil painting technique that accompanied the described evolution of the support. With the canvas as support, oil painting became ‘painterly’, i.e. brush-strokes were left visible. This interesting fact we’ll come back to in another post.