How would an overdeveloped radiograph most likely appear?

An overdeveloped radiograph typically exhibits excessive density due to the prolonged exposure to the developing solution or an overly high developing temperature, which leads to more fogging and increased blackening of the film.

In this scenario, the radiograph appears dark because the increased amount of metallic silver from overdevelopment reduces the film's contrast. While there may be some faint images visible, the predominant characteristic is the darkening of the film, which limits the clarity and detail that can be assessed.

Thus, the appearance of an overdeveloped radiograph is dark with some image detail, aligning with the characteristics described.