Tip: Painting With a Knife

Painting with a knife is a bit like spreading icing on a cake. Although a painting knife can be used with any paint, it is most effective with paint that is relatively stiff, like butter or icing (such as, oil and acrylic paints). As you might imagine, knives produce quite a different texture and effect than do brushes. For instance, knives are excellent at applying thick impasto strokes, creating sweeping areas of clean color, and making tiny shapes as well.

Painting with a knife is not particularly difficult to learn. In fact, some aspects of painting are greatly simplified when using a knife. For example, knives are much easier to clean than brushes. Just wipe away any excess paint from the blade using a cloth or paper towel. Even if you let the paint dry on the knife, it can be easily removed by scraping it with a damp cloth, fingernail, or another knife. However, if a knife is made from steel rather than stainless steel, it may rust if you leave water-based paints to dry.

Here is how you paint using a knife:

1. Mix your paint as you normally do using a palette knife. You may also use the painting knife for this purpose if it has a large enough blade.
2. With a clean knife, pick up a small amount of paint from your palette near the tip on the edge of the blade. It should feel something like taking a small amount of butter from a butter plate. 
3. Using the side of the blade, spread the paint across your canvas. This stroke can be light or heavy. A light touch will allow the paint to be pulled from the knife by the weave of the canvas. Increase the pressure and you can scrap the paint accross the surface, leaving paint only between the fibers. You can vary the touch depending on the effect you want to acheive.
4. You can also press paint onto the canvas by pushing the blade flat against the canvas.
5. Using only the tip of the blade to pick-up and apply the paint, you can produce small dots of color. Using only the the edge of the knife while moving the knife in the same direction as the blade, you can produce very fine lines. 
6. A clean blade can also be used to scrap layers of existing paint to expose the canvas or lower levels of paint (see s'graffito).
7. If you let the painted surface dry, the canvas can be lightly sanded making it easier to apply a second layer of paint.

Be careful to note that the edge of a painting blade becomes sharper the more it is used. If the blade becomes too sharp, or if the blade breaks, you can grind-down the edge to make a smaller blade.

Georg Miciu-Nicolaevici, Detail of "La Yunta" (The Pair)