Radiography utilises very short wavelength electromagnetic radiation, namely X-rays or ? rays, will penetrate through solid media but will be partially absorbed by the medium. The amount of absorption which will occur will depend on the thickness and density of the material the radiation is passing through, and also the characteristics of the radiation the radiation which passes through the material can be detected and recorded on either film or sensitized paper, viewed on a fluorescent screen or detected and monitored by electronic sensing equipment.