What happens when intensifying screens are used?

When intensifying screens are used in radiography, they play a significant role in the imaging process by enhancing the effect of the X-rays on the film. The correct answer indicates that intensifying screens can produce halation and result in a loss of spatial resolution. This is because intensifying screens convert X-ray photons into visible light, which then exposes the film. If the film is not properly aligned or if there is excessive light scattering within the screen or film, halation can occur. Halation refers to the unwanted spreading of light beyond the intended area, which can blur the image and decrease spatial resolution. This blurring occurs because the visible light emitted from the screen can extend into areas where it does not contribute to the image formation, thus compromising the sharpness and clarity of the resulting image.

In contrast, the other options do not accurately reflect the effects of intensifying screens. Using intensifying screens does not directly increase electron speed, provide enhanced radiation protection, or reduce image contrast as primary outcomes. Instead, they primarily improve the efficiency of image production by requiring less radiation exposure, but this can lead to challenges in maintaining image quality due to factors like halation.