The optical density resulting from an unexposed film processed through the fixer, washer, and dryer without passing through the developer is termed what?

The term that describes the optical density of an unexposed film that has gone through the fixer, washer, and dryer without being developed is known as base density. Base density refers specifically to the inherent density of the film base material itself, which is how much light is absorbed by the film without exposure to radiation. This density is observed in undeveloped film and represents the lowest level of optical density achieved when the film has no latent image.

In contrast, the other terms provided refer to different concepts. For instance, base plus fog density takes into account both the film base density and any unintended density due to fogging from handling, light exposure, or chemical interactions during processing. Mid density generally refers to a specific range of optical density values achieved under certain exposure and processing conditions, whereas density difference pertains to the contrast or difference in densities between exposed and unexposed areas of the film, not applicable to a film that has not been developed at all. Understanding these distinctions helps in the interpretation of radiographic films and is crucial for ensuring quality in radiographic imaging practices.