Which diluent is considered the most common in oil painting?

In oil painting, turpentine is considered the most common diluent due to its ability to thin oil paints effectively while enhancing their flow and drying time. Turpentine is a solvent derived from the resin of pine trees, which makes it particularly well-suited for use with oil-based paints. When artists use turpentine, they can achieve various effects, from transparent washes to more opaque applications, depending on the amount used.

Additionally, turpentine helps maintain the paint's adhesion to the canvas and supports the overall texture and finish of the artwork. Its strong solvent properties also mean that it efficiently dissolves the oil components in the paint, allowing for smoother application and blending.

While mineral spirits and other options may also be used as diluents in oil painting, turpentine has a longstanding tradition and is frequently preferred by traditional painters for its specific qualities and historic significance within the practice.