The process of oil painting varies from artist to artist, but often includes certain steps. First, the artist prepares the surface. Although surfaces like linoleum, wooden panel, pressed wood, and cardboard have been used, the most popular surface is canvas. While many famous paintings were painted on panel (for instance Da Vinci''''s Mona Lisa), the size of the work is immutable and this often makes transportation cumbersome. Stretched canvas, on the other hand, can be unstretched and rolled for easier transportation.

Traditional artists'''' canvas is made from linen, but the less expensive cotton fabric has gained popularity. The artist first prepares a wooden frame called a ��stretcher" or "strainer." The difference between the first and second is that stretchers are slightly adjustable, while strainers are rigid and lack adjustable corner notches. The canvas then pulled across the wooden frame and tacked or stapled tightly to the back edge. The next step is for the artist to apply a ground (or size) to isolate the canvas from the acidic qualities of the paint. Traditionally, the canvas was coated with a layer of rabbit skin glue and primed with subsequent layers of finely ground chalk (or marble dust) and rabbit skin glue. Later the process was changed to a sizing of rabbit skin glue with subsequent layers of white priming (gypsum, chalk, barium oxide, titianium(IV) dioxide mixed with linseed oil). Modern gessos are made of titianium dioxide with an acrylic binder and are not "real" gessos in the true sense of the word. The artist might apply several layers of gesso, sanding each smooth after it has dried. Sanding the primed surface is important to roughen the generally slick surface so the subsequent layers of oils will properly adhere. It is possible to tone the gesso to a particular color, but most store-bought gesso is white. The gesso layer will tend to draw the oil paint into the porous surface, depending on the thickness of the gesso layer. Excessive or uneven gesso layers are sometimes visible in the surface of finished paintings as a change in the layer that''''s not from the paint.

Next the artist might sketch an outline of their subject prior to applying pigment to the surface. ��Pigment�� may be any number of natural substances with color, such as sulfur for yellow or cobalt for blue. The pigment is mixed with oil, usually linseed oil but other oils may be used as well. The various oils dry differently creating assorted effects.

Traditionally, an artist mixed his or her own paints for each project. Handling and mixing the raw pigments and mediums was prohibitive to transportation. This changed in the late 1800��s, when oil paint in tubes became widely available. Artists could mix colors quickly and easily without having to grind their own pigments. Also, the portability of tube paints allowed for plein air, or outdoor painting (common to French Impressionism).

The artist most often uses a brush to apply the paint. Brushes are made from a variety of fibers to create different effects. For example, brushes made with hog��s bristle might be used for bolder strokes. Brushes made from miniver, which is squirrel fur, might be used for finer details. Sizes of brushes also create different effects. For example, a "round" is a pointed brush used for detail work. "Bright" brushes are used to apply broad swaths of color. The artist might also apply paint with a palette knife, which is a flat, metal blade. A palette knife may also be used to remove paint from the canvas when necessary. A variety of unconventional tools, such as rags, sponges, and cotton swabs, may be used. Some artists even paint with their fingers.

Most artists paint in layers, a method first perfected in the Egg tempera painting technique, and adapted in Northern Europe for use with linseed oil paints. The first coat or "underpainting" is laid down first, painted normally with turpentine thinned paint. This layer helps to "tone" the canvas, and cover the white of the gesso. Many artists use this layer to sketch out the composition. This layer can be adjusted before moving forward, which is an advantage over the ''''cartooning'''' method used in Fresco technique. After this layer dries, one way the artist might then proceed is by painting a "mosaic" of color swatches, working from darkest to lightest. The borders of the colors are blended together when the "mosaic" is completed. This layer is then left to dry before applying details. After it is dry, the artist will apply "glazes" to the painting, using a process of "Fat over Lean" which means more oil/paint ratio than the previous layer. A classical work might take weeks or even months to layer the paint. Artists in later periods such as the impressionist era often blended the wet paint on the canvas without following the Renaissance layering and glazing method. This method is called "Alla Prima." When the image is finished and dried for up to a year, an artist would often seal the work with a layer of varnish typically made from damar gum crystals dissolved in turpentine. Contemporary artists increasingly resist the varnishing of their work, preferring that the surfaces remain varnish-free indefinitely.