What is the main cause of a pale x-ray image in dental radiography?

A pale x-ray image in dental radiography is primarily caused by underdeveloping. When radiographic film is not properly developed, it may not achieve the necessary contrast and density, resulting in images that appear washed out or pale. This can happen if the film is not exposed to the developer for the correct amount of time or if the temperature of the developer solution is too low, which can prevent the chemical reactions necessary for creating a properly developed image.

While old expired film can affect image quality, it typically results in fogging or decreased sensitivity rather than a uniformly pale image. Overexposure would lead to a darkened image rather than a pale one, and improper positioning may cause parts of the image to appear distorted or unclear, but it would not result in a uniform pale appearance across the entire x-ray. Thus, underdeveloping is the primary factor that creates a pale appearance on the x-ray.