Abstract: A process and apparatus for measuring pipe wall thickness wherein a film sheath is placed beneath the pipe section to be inspected and a radiographic stream is projected from a camera through the pipe to the film pack. Gamma radiation is exemplary in this process. There is further provided a comparative scale which comprises a scale portion, normally constructed of brass or the like material having a plurality of cuts through the scale body representing a scale in twenty thousands of an inch (0.20 inches) increments. This scale body, for purposes of enabling accurate radiography, is encased between an upper and lower layers of carbon steel or other material, the entire layer being encased in a plastic or the like encasement sheath. During the process, the comparative scale is placed adjacent the area of pipe to be radiographed. Following the radiographing of the pipe and comparative scale, the resulting graphic produced indicates the pipe thickness adjacent the comparative scale.