Which of the following causes elongation in radiographic images?

Elongation in radiographic images occurs when the image appears stretched or longer than it actually is. This phenomenon is primarily caused by insufficient vertical angulation. When the x-ray beam does not have the appropriate angle in relation to the object being radiographed, the resulting image does not accurately depict the true size and shape of that object. Specifically, if the vertical angulation is too shallow, the image created will elongate the structure, leading to a misrepresentation in size.

In dental radiography, for instance, if a clinician is taking a periapical radiograph of a tooth and does not have the film or sensor angled appropriately, the tooth can appear longer than its true size. This is particularly crucial in clinical settings where accurate representation of anatomy is necessary for diagnosis and treatment planning.

The other options, while they may affect the quality of the image, do not specifically cause elongation. Excessive horizontal angulation typically results in distortion or overlap of structures rather than elongation, whereas excessive exposure time and inadequate film processing might lead to issues such as overexposure or underexposure, or image artifacts, which do not manifest as elongation.