What does it indicate if a film appears blank during manual processing?

When a film appears blank during manual processing, it typically indicates that it was placed in the fixer solution before going through the developer. The fixer solution makes the emulsion on the film insensitive to light, effectively removing the latent image that would have been developed by the developer. Therefore, if the film is exposed to the fixer first, it cannot undergo the development process correctly, resulting in an entirely clear or blank image.

In contrast, other factors such as correct exposure, underexposure, or overdevelopment do not explain a completely blank film. Correct exposure would typically lead to an image, while underexposure would result in a faint image rather than a blank film. Overdevelopment might cause an image to appear very dark or too dense but would not cause it to be entirely blank. Thus, the placement of the film in the fixer before the developer is the primary reason for a film appearing blank after manual processing.