Radiography is an X-ray imaging technique that allows to visualize the internal structure of an object. The absorption of X-ray is dependent on the density and composition of the different parts contained in the object, giving rise to the contrast in the radiograph.
Radiography has been the first technique developed using X-rays. In fact, one of the first experiments performed by Röntgen shortly after the discovery of X-rays was collecting an image of the hand of his wife. The medical applications of radiography have made this technique blossom in the 20th and 21st century, and it is still a powerful tool largely used in hospitals all over the world.
Moreover, radiography is used in material science being the basic technique Computed Tomography is based on.