Radiography is a nondestructive testing method (symbol RT) of obtaining an image of an object through which electromagnetic radiation X or gamma. The image is obtained by a detector which is usually a silver film. This is a comprehensive approach to internal defect detection mainly.

The principle of the method is based on the absorption of the medium as a function of the atomic number of the atoms of the component and the density. Any lack of material will induce a lower absorption and therefore, locally a higher optical density on the film or a higher gray level in the case of digital images.

In industrial radiography, X -rays are produced usually by a X-ray tube The gamma sources are used industrially iridium 192, cobalt 60 and selenium 75.

Due to the nature of ionizing X or Gamma rays, strict radiation protection requirements apply.

See also the ultrasound technical substitution especially radiography the TOFD and Phased Array method.