Oil Painting Approaches
Painting on toned grounds is a classical approach that uses thinner layers of paint. This leads to a finished product that is less expensive but more durable. However, it demands careful planning on the part of the artist. Changing ideas in the middle of painting would be disastrous and the toned ground would only make such "afterthoughts" obvious.
There are various approaches to oil painting, and among them, the three most popular are "painting on light grounds", "painting on toned grounds" and "painting on dark grounds"

Painting on toned grounds is a classical approach that uses thinner layers of paint. This leads to a finished product that is less expensive but more durable. However, it demands careful planning on the part of the artist. Changing ideas in the middle of painting would be disastrous and the toned ground would only make such "afterthoughts" obvious.

This approach also demands great dexterity in the artist's ability to use the paint brush. After the major part of the painting has dried, repainting with finer details is done. And then, glazing, thickening, and widening are performed in areas where these are needed. Rubens used this approach in many of his masterpieces.

Painting on dark grounds is another classical approach that is used to produce a chiaroscuro effect. First, the ground (or blank canvass) is darkened. This hue will serve as shadows and will add to the dimensions of objects drawn over it. Once the dark ground is dry and a sketch is drawn over it, underpainting with grisaille is done. Grisaille refers to shades of gray.

Over the grisaille, frotties (semi-transparent paints) are used to tone several areas. Next, the upper paint layers, composed using light colors, are applied, and sometimes using the impasto technique.

Impasto is having thick paint standing out prominently and Van Gogh was known to use this technique in many of his works. Finally, the whole composition is covered with multi-colored glazes.

Painting on light grounds has two distinct methods: the Pre-Raphaelite and the Direct painting approach. In the Pre-Raphaelite approach, the white ground is used to achieve a stained-glass effect. Over the white ground, the sketch is done and very little body color is used over it. Once dry, strong-colored glazes are applied.

Direct painting is an oil painting approach popularized in the late 19th century. Contrary to what it implies, the direct painting approach usually proceeds in stages, although there are a few cases in which a composition can be completed in one session.

There are three distinct characteristics attributed to this approach. First, the blank canvass is painted white, similar to the Pre-Raphaelite approach. But this is then painted over opaquely and completely. This step is called "covering the ground". Second, the white pigment is used throughout the composition. And third, no glazing is involved. The final touches just involve fine painting using a soft brush.