JIS Z 2343-1:2017 specifies a method of penetrant testing used to detect discontinuities, e.g. cracks, laps, folds, porosity and incomplete fusion, which are open to the surface of the materials and products in manufacturing process or in service (hereafter referred to as parts to be tested), and also specifies classification of penetrant indication by discontinuities. Testing is mainly applied to metallic materials, but can also be performed on other materials, provided that they are inert to the test media and not excessively porous, for example, castings, forgings, welds, ceramics.