Friday, 6 March 2009

Supports for oil painting

This article was first published in "Frequency Magazine" – February 2008.

Supports are either flexible (like canvas) or rigid (like wood). The support you use has a direct incidence on the look of the finished painting and some supports are more suitable for specific techniques. When choosing a support, you should also think about conservation as well as transport and storage. Before you ask: there is no ideal support; they all have advantages and shortcomings. This article will help you to select one or several supports that work for you.

- Canvases: Canvases are flexible and have a good size-to-weight ratio. Cotton canvases are a popular choice as they are less expensive than linen canvases. Acrylic primed canvases can be used for both oil and acrylic. Canvases made of cotton have a smoother surface than linen ones. There are various qualities and grades of cotton and, for larger sizes, you need to make sure that the fabric is strong enough and springs back when you push lightly on it with your finger. Look at the back to make sure the canvas is knit with a close and even weave.

Linen canvases are more expensive but remain the material of choice for professional painters. Linen fibres are longer, remain flexible for longer, are resistant to bacterial rot and are less affected by the atmosphere. Linen canvases have an irregular and pronounced texture when woven that makes impasto work easier, as the paint sticks to the coarser surface. On the other hand, cotton canvases work best for detailed brushwork and subtle glazes.

Apart from traditional canvases, you also find in shops deep-edge canvases. The canvas is wrapped on all sides of the stretcher bars. You can keep the edges clean or paint on them and these canvases are often exhibited without any frame (which makes then a cheaper option). Using these deep-edge canvases rather than traditional canvases is a matter of taste and style.

On the minus side, canvases are more prone to damage if mishandled. To avoid denting the canvas, store them vertically and don’t lean anything against the fabric.

- Wood: Wood has been used as the main support for oil paintings until the early 16th century and continued to be used even after canvases were invented. Painters have painted on poplar, oak, walnut, cherry and other types of wood. Wood must be fully dry and properly prepared and stored as it is affected by climate changes and can crack when subjected to intense heat. Stay away from planks with nodes as these may show through the paint. Finally, large wood panels are prone to warpping. Good wood is expensive and is not favoured by painters today.

- Wood substitutes: Modern wood substitutes like plywood and hardboards make excellent supports. You just need to prime them with several coats of acrylic gesso. This can be a cheap option if you buy off-cuts from a hardware store. The surface obtained after sanding is smooth and rigid. If you’re looking to create a highly textured painting, the rigid surface will reduce the risk of cracks. This surface is also ideal if you want to scratch the surface of the painting with a blade to reveal prior layers (canvases would be too fragile for this type of handling). If you want to go wild, you don’t have to limit yourself to rectangles and squares; almost any shape can be obtained with a jigsaw power tool.

The drawback of hardboards is their weight, which makes them impractical to use for large formats. Plywood is lighter but can warp if used in a large size. Plywood, hardboard and MDF work well for small formats and are great to make your own panels.

- Panels: Panels take less space than stretched canvases and are ideal if you are going away on a painting trip. You can buy some in art shops or make your own by gluing canvas onto a piece of MDF.

- Paper: Bonnard and Turner painted oils on paper. Watercolour paper with a weight of 300gsm/140lbs or heavier can be used for oil painting. It is very important to use an acid free paper for good conversation and then to prepare it with two coats of acrylic gesso (dilute the first coat with water to obtain good coverage and retain the texture of the paper. When the first layer is dry, apply a second layer with less diluted gesso), otherwise the chemicals and acidity in the oil paint will damage the paper in the long term. Paper is light and takes minimal storage space. It is a good option for studies and sketches. For a finished work, it can be mounted on a board and framed under glass.

- Other supports: Copper (which has to be scratched slightly to create some tooth) has been used for small detailed work. To get the best of it, paint with transparent colours so that the copper will shine through. Toulouse-Lautrec used unprimed cardboard, probably because it was cheap, dried quickly (the solvent being absorbed by the cardboard) and gave to his works a mat finish reminiscent of pastel paintings. You can also paint on slates, which give a deep grey textured background.

The best way to decide is to try your hand on different types of surfaces, hard or flexible, rough or smooth, and find the ones that work for you. I suggest you start with ready made cotton canvases. Art shops offer many good quality canvases at affordable price, so try out different brands to find your favourite one that matches your work process.

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