A liquid penetrant used to obtain an outline of fractures within the metal surface. To perform the test, a thin oil-like liquid containing a dye is applied by a brush, flow, or dip method; the liquid moves into small openings or cracks during a penetration time (1-30min). After the excess liquid on the surface is carefully removed and the object is dried, a developer is applied to the surface. This material is typically a fine powder, such as talc, usually in suspension in a liquid. It acts like a blotter and pulls the liquid penetrant out of surface imperfections. The liquid tends to spread in the developer, enlarging the indication.