In radiography, which factor primarily impacts the density of the developed film?

The factor that primarily impacts the density of the developed film is the developing time. Density in radiography refers to the degree of darkness on the film after it has been processed. During the developing phase, the film's sensitivity to light and the latent image that was created during exposure is made visible through chemical reactions.

When the developing time is too short, there may not be enough development of the silver halide crystals in the film, resulting in a lighter appearance and lower density. Conversely, if the developing time is too long, the film can become overdeveloped, leading to excessive darkness and high density. Therefore, controlling the developing time is critical in achieving the desired film density and ensuring accurate radiographic results.

While other factors like washing time and fixing time contribute to the overall quality of the film, they do not directly affect the film's density as significantly as developing time does. Exposure time primarily influences how much radiation interacts with the film, which affects the initial formation of the latent image but not the final density after processing. Thus, the correct choice is developing time, as it has the most pronounced effect on the density of the developed film.