Which factor would NOT cause an underexposed film?

Excessive mA, or milliamperage, increases the number of x-ray photons produced during exposure, which generally results in a denser image on the film. When the mA is high, there is a greater quantity of x-ray radiation reaching the film, which contributes to proper exposure rather than underexposure.

In contrast, insufficient exposure time and insufficient kVp (kilovolt peak) can lead to underexposure by either not allowing enough time for x-rays to hit the film or not providing enough energy for the x-rays to penetrate the subject adequately. Wrong film placement can also result in underexposed areas if the film is not positioned correctly to receive the radiation. Each of these factors directly relates to the effectiveness of the x-ray exposure in capturing an accurate image, while excessive mA ensures that the film will be exposed properly.