Physics and chemistry of film and processing.

An image containing the equivalent of almost 1 billion digital bits of diagnostic information can be recorded and displayed on a single sheet of film with use of a high-resolution screen-film radiographic system. The information storage capacity, versatility, and very low cost of screen-film radiographic systems are impressive. However, the inherent coupling of the recording and display functions does not allow optimization of these two functions independently, and this limitation has important implications for optimizing the radiographic image. The photographic process, including latent image formation and chemical development of that latent image, depends on many complex, time- and temperature-dependent phenomena that must be taken into consideration for optimizing the diagnostic image. Once the diagnostic image is processed and ready for viewing by transillumination, the complex response of the human eye requires careful attention to viewing conditions to optimize the information transfer from the film to the human observer.