Oil painting can be done on linen sheet, masonite board or canvas. All the three mediums are very good to use and are known to last long. My favorite medium is canvas. I do the stretching and apply primer. Once after the primer is applied, the canvas is rubbed with salt paper to even out the pores and to remove unwanted blobs on the canvas. I start everything, the whole process of treatment from the scratch. Then apply few layers of primers and a strong layer of the darkest oil color. That way I will be able to measure all the values against the darkest value as reference. This site has all my canvas paintings for sale.
There are several types of canvases available in the market. It is very important to handpick the right canvas. There should not be blobs or pores in the canvas. The presence of blobs will spoil the beauty of the painting. A painting with pores will never get sold. It is better to handpick canvases that are thick in nature. No matter how the canvas is, it is essential to apply a few layers of primer or acrylic on the canvas so that the oil that is applied on the canvas does not corrode the canvas as time goes on. This website has all my oil paintings on canvas for sale.