How does doubling the exposure time affect radiographic contrast?

Doubling the exposure time primarily influences the amount of radiation reaching the film or digital sensor. As exposure time is increased, the density of the radiographic image increases because more x-rays are absorbed. However, it does not significantly alter the inherent contrast of the image.

Contrast in a radiographic image is determined by the difference in density between adjacent areas, which is influenced by factors such as the kilovoltage peak (kVp), the type of film or sensor used, and the processing of the image rather than merely the exposure time alone. Therefore, while increasing exposure time will make the image denser, it will not change the contrast since the relationship between the light and dark areas remains proportional.

Thus, doubling the exposure time has no effect on radiographic contrast, affirming that it maintains the same contrast characteristics as the original exposure.