What aspect of radiographic images can be improved by adjusting beam filtration?

Adjusting beam filtration primarily affects image contrast in radiographic images. Filtration refers to the process of selectively removing lower-energy photons from the X-ray beam before it reaches the patient and the image receptor. This is essential because lower-energy photons contribute more to patient dose without significantly enhancing image quality, as they are more likely to be absorbed by the patient's tissues and do not contribute to the formation of the image.

By removing these less energetic photons, filtration increases the overall quality of the beam, allowing only higher-energy photons to pass through. Consequently, this leads to an increase in the contrast of the image, as the differences between the various tissues are more clearly delineated. With better contrast, subtle differences in tissue density can become more apparent, aiding in the diagnostic process.

Brightness, sharpness, and size, on the other hand, are more influenced by factors such as exposure parameters, the characteristics of the imaging system, and the distance between the source and detector. Adjusting beam filtration primarily impacts the quality of the image in terms of contrast, making the correct answer focused on this aspect.