ASNT RT Level II Practice Test 2025 – Comprehensive Exam Prep

Kilovoltage is the technique variable most commonly used to adjust subject contrast in radiography. The kilovoltage peak (kVp) setting controls the energy of the X-ray beam produced. When the kVp is increased, the penetrating power of the X-rays also increases, which tends to reduce the contrast of the radiographic image. This is because higher energy X-rays are less likely to be absorbed by the denser materials in the subject, leading to a more uniform exposure across different materials and thus reduced contrast.

On the other hand, adjusting kVp allows for flexibility to achieve the desired subject contrast based on the specific characteristics of the material being radiographed. By selecting an appropriate kVp value, an operator can optimize the balance between penetration and contrast, ensuring that the necessary details are revealed in the final image without excessive overexposure.

The other factors listed, such as exposure time, filtration, and source size, can affect the quality and density of the image but are not primarily used for adjusting subject contrast. Exposure time mainly influences the overall exposure of the film or detector, filtration alters the beam quality by removing lower-energy photons, and source size affects the resolution and sharpness of the image. Each variable plays a role in radiographic quality,