X Ray imaging question

X-ray (photons penetrate patient (1)
attenuation by different media / bones attenuate more than soft tissue (1)
less X-ray reach film under bone / shadow effect (1)
intensity of X-rays is proportional  to darkening of film / ref. To fogging or
blackening (1)

          X-ray photons hit crystals / atoms in intensifying layer (1)
atoms become excited / fluorescence occurs (1)
emitting light (photons) (1)
detail: as they return to ground state (1)
so extra fogging of film (1)
detail: metal backing stops X-rays passing through / film more sensitive to light
than X-rays / most X-rays pass through the film / double sided / photographic
film / more contrast but not clearer (1)

          Response is quicker / less X-rays needed (1)
so less exposure (1) to maximum of 8                                                                              8

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