Which of the following is a method for improving image sharpness in radiography?

Using lead screens is an effective method for improving image sharpness in radiography primarily because lead screens enhance the contrast and reduce scattered radiation, which can blur the image. When a lead screen is placed behind the film, it absorbs scattered radiation that could otherwise contribute to image fogging and a lack of sharpness. This results in a clearer, more defined image where the details are enhanced, allowing for better interpretation of radiographic findings.

While other methods like reducing film-to-focal distance can also contribute to increased sharpness by minimizing the effects of geometric distortion, it doesn't directly address issues caused by scatter. Increasing exposure time typically does not improve sharpness but can lead to overexposure if not carefully controlled. Decreasing the mA setting can result in a decrease in the quantity of radiation reaching the film, which may lead to a poorer image quality rather than improve sharpness.