CR uses an imaging plate coated with storage phosphors to capture x-rays as they pass through the patient. Trace amounts of impurities are added to the phosphor materials in a process called "doping," to alter their crystalline form and physical properties. When irradiated, the enhanced phosphors absorb and store x-ray energy in gaps in their altered crystal structure. This trapped energy comprises a latent image; when stimulated by additional light energy of the proper wavelength, the trapped energy is released.

Radiography principle relies on penetrating radiation (X, gamma, neutrons, …) generated by a source, more or less absorbed in the testpiece to be inspected.