Which factor contributes to providing a low subject contrast during radiographic imaging?

In radiographic imaging, subject contrast refers to the differences in radiographic density that allow various tissues to be distinguished from one another on the image. High kilovoltage settings lead to a lower subject contrast because they increase the penetrating power of the X-ray beam. This means that the beam can pass through different types of tissues with less attenuation, causing more uniform exposure across the image.

The result is that soft tissues and bone, which have inherently low contrast, become less distinguishable due to the evenness of exposure. When high kilovoltage is used, it generates a wider range of X-ray photon energies, which can further contribute to overlapping densities on the radiograph and make it more challenging to differentiate between structures. Thus, high kilovoltage settings are linked to lower subject contrast in radiographic images.

In contrast, lower kilovoltage would typically increase contrast because it creates more differential absorption between tissues of varying densities.