Selection of proper kVp is influenced most by which two of the following?

size of patient and density of tissues
size of film
distance of tubehead to patient
developing temperature

size of patient and density of tissues

Rationale: size of patient and density of tissues – kVp determines the quality of the radiograph, so patient tissues and size affect the density. The more the kVp is increased, the shorter the wavelength and the higher the energy and penetrating power of the x-rays produced.