Canvas Painting - History and Preparation
Today, canvas is the most common medium for oil paintings. However, was this always so? In fact, it wasn't. Before the Renaissance period (approx. 1400-1700) all paintings were done on more solid mediums, such as wood. However, during the time of the Italian Renaissance, the merchant shipping industry was booming, and with that boom came many innovations and technologies borrowed from more eastern cultures. Among these technologies was the use of the canvas sail.
Canvas was originally made out of hemp. In fact the word 'canvas' originally derived from the Arabic word for 'cannabis,' a Latin term translating to 'hemp' (this is also the name of the family of plants from which hemp is made). This strong material was made by tightly weaving the cannabis fibers together. The result was a strong fabric that could be used for sails and tents.
With the sudden success of the merchant industry, canvas became readily available to the public. Canvas was probably first used by portrait artists in Venice around 1500 AD. Canvas painting quickly took popularity over the more traditional and cumbersome wood planks. Because of its durability, canvas was able to withstand both the paint itself and the test of time. Not to mention canvas is more portable, less expensive, and easier to create the correct size. No longer was an artist inhibited by the size of the wood plank he could find, and much larger paintings resulted from this freedom.
During the late 18th and early 19th centuries American cotton had become more readily available and popular for the European artist. Yet artists still preferred the stronger linen or hemp for their oil paintings, despite the higher cost. At the time cotton fibers were weaker than either linen or hemp. Especially true when cotton was wet, it tended to be more prone to mildew. Only within the last hundred or so years has advancing technology finally brought cotton canvas to a more popular position than linen and hemp.
Preparing your canvas painting
Modern canvas is made from cotton, linen or synthetic material. In its natural, unprimed state, cotton canvas is an off-white color, and the finer linen canvas is a light brown. Both can be purchased in varying weights and qualities, are the least expensive to buy, but the most time-consuming to prepare. It is also possible to buy primed, non stretched canvas, as well as canvas panels, which are already primed, and ready to paint on when purchased. There are also non-stretched canvases available in arts and crafts stores, some office stores, and department stores.
In preparation for a canvas painting, the canvas is first stretched and secured over a wooden stretcher frame (stretcher bars). When stretching your own canvas for an oil painting, four stretcher bars and up to 8 keys are needed to get a proper stretching up to 20 - 24". Stretcher bars come in ready made sizes from eight inches to forty eight inches. For canvas longer than 20 -24" inches a mid bar is recommended and for canvas larger than thirty inches, the heavier duty stretcher bars with cross panels are recommended. The keys usually come with the stretcher bars and help to hold the canvas more securely in place at the corners. The artists hammer is used to join the bars and heavy duty staples are used to secure the canvas in place. Canvas pliers are used to grip tightly the canvas during the stretching process and a right angle is necessary to be sure that the final product is perfectly square. The process is a little more time-consuming, but in the long run will save the artist money in art supplies.
The surface of the canvas then receives a smooth coat of white calcium sulfate, plaster of paris, sealed with a glue, known as gesso. This is to seal the canvas and prevent the fibers from absorbing too much of the paint. This coating of gesso is generally followed by the pigment lead white, which secures upper pigments. Without this priming, the fibers of the canvas would soak up the paint and create a 'stained' appearance. Some modern artists actually prefer this look and use unprimed canvas for painting.