What is an Oil Painting?
When we think of painting we usually think of oil painting. All there are a number of different types of paints that can be used oil painting is the one we usually think about. This is mainly because almost all of the famous artists of the renaissance period used oil paints.
Oil painting is well not surprisingly a painting done with oil. Actually it uses oil to carry the colours. When we paint we use pigments to make the different colours. You need to have some sort of a liquid substance that you can use to carry the colours so that you can apply them. The two most commonly used liquids are water, from which we get water colours and oil which gives us oil painting. The advantage that oils have over water is that you can can use a variety of different oils that all have different properties. This allows for more variations is colour and shades and it also allows for different textures on the surface of the painting.
In the early days of oil painting artists used to actually make their own paints. They would mix the pigments with the oil themselves. This gave them great control over the colour of the paint but it made the job much more difficult. It also limited where you could paint since it wasn't like you were going to haul a full array of oils and pigments with you. That pretty much limited painting to the studio. It also pretty much eliminated things like landscapes as subject matter. That all changed in the early nineteenth century when pre-mixed oil paints started to become available in tubes. This meant the artist could paint anywhere that he wanted to. It also opened up a far wider range of subject matter.
Most oil painting is done on a canvas, traditionally this is made out of linen. However in recent years cotton has become widely used because it is cheaper. The canvas is usually stretched onto a wood frame before the painting starts. You can't apply oil based paints straight to the canvas since the acid in the paint will ruin the canvas. Before they start the painter will apply an animal glue to the canvas. They will then add several layers of white lead based paint as a primer. Finally they will add several layers of acrylic to the canvas. The acrylic layer needs to be sanded down before the painting can start.
Once the canvas is ready for painting the normal technique is for the painter to sketch an outline before he starts to paint. Then he will normally add several layers of paint, this is a big part of what makes oil painting so distinctive. After the painting is finished it normally needs to be left for up to a year to dry. Once this is done a layer of varnish is normally added to protect the painting.