The primary controlling factor for contrast in film-based imaging is kilovoltage or kV. Kilovoltage controls the energy or is the penetrating power of the primary beam. The higher the kV, the greater is the energy and the more uniformly the x-ray beam penetrates the various mass densities of all tissues. Therefore the higher kV produces less variation in attenuation (differential absorption), resulting in lower contrast.

Kilovoltage (kV) is also a secondary controlling factor of Click Here To Read More