Which factor is NOT a common influence on the quality of radiographic images?

The quality of radiographic images is influenced by multiple factors that directly affect the clarity, contrast, and overall visibility of the internal structures being examined. Among the listed factors, moisture density treatment (MDT) is not typically recognized as a common influence on radiographic image quality.

In radiography, key elements such as film processing time, distance between the radiation source and the film, and exposure settings play critical roles. Film processing time affects the development of the radiograph, with underdeveloping or over-developing potentially leading to poor image quality. The distance between the source of radiation and the film impacts the intensity of radiation that the film receives; a greater distance can result in a decrease in the image density and potentially cause blurring. Exposure settings, including time, voltage, and current, directly contribute to the amount of radiation that reaches the film, thereby influencing the film's contrast and detail.

Since MDT is not a standard factor impacting image quality in the context of traditional radiographic testing, it stands out as the correct answer in this scenario.