The basic principle of liquid penetrant inspection method; It is based on capillary actions where low surface tension fluidity penetrates clean and dry surface breaking continuities. Penetrant; It can be applied to the component to be inspected by dipping, spraying or brushing. After sufficient penetration time is allowed, excess penetrant is removed and a developer is applied. The developer assists in removing the penetrant from the defect so that an invisible indicator becomes visible to the practicing specialist. Inspection is carried out under ultraviolet or white light, depending on the type of paint used.