''Oil and acrylic on canvas" refers to a painting technique where oil or acrylic paint is applied to a canvas surface. Canvas is a popular support for painting because it is durable and easy to stretch, making it ideal for creating large works. Oil paints are made from pigments that are suspended in a medium of drying oil, such as linseed oil. Acrylic paints, on the other hand, are made from pigments that are suspended in a water-based medium. Both types of paints are versatile and can be used to create a wide range of effects, but they have different working properties, such as drying time and texture.

The technique used when creating a painting with oil or acrylic on canvas can vary depending on the artist's preference and the desired outcome of the piece.

For oil paintings, artists often begin by priming the canvas with a layer of gesso, which is a mixture of white pigment and a binder. Then they will sketch out the composition and underpaint the piece with a thin, transparent layer of paint called a "thin wash." This allows the artist to establish the basic tones and colors of the painting before applying thicker, more opaque layers of paint.

Oil paint dries slowly, which allows the artist to blend and layer the paint, creating a smooth, gradual transition between colors. This technique can be used to create a wide range of effects, from photorealistic details to more abstract and expressive brushstrokes.

For acrylic paintings, artists may also use the same technique of priming the canvas and sketching the composition out. Acrylic paint dries quickly, so artists will have to work in a more spontaneous manner and in a shorter time frame. They may use thicker paint and palette knives to create texture, or use water to thin the paint and create a watercolor-like effect.

Both oil and acrylic painting techniques have their own characteristics and it's up to the artist to choose the one that suits their personal style and the piece they are creating.