Film Artifacts

Table 6-18. Description of Film Artifacts

TM-1-1500-335-23 Nondestructive Inspection Methods Manual
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T.O. 33B-1-1 6-86 6.7.19 Film Artifacts. An artifact is the product of human error and, in the case of film, is usually due to mishandling of the film in some step in the radiographic process. 6.7.19.1 Processing Artifacts. Chemical spots can occur if any chemicals are splashed, contacted, or transferred by wet fingers to the undeveloped film. Dark spots indicate either water or developer on the film before processing. Light or undeveloped spots indicate that the stop bath or fixer has been allowed to contact the film before processing. Stains caused by chemical reactions, over development or underdevelopment, are processing artifacts. Streaks from contaminated hangers are quite common as well as streaks from lack of agitation during the development period. 6.7.19.2 Handling Artifacts. Many artifacts are introduced by film handling. Crow-foot static marks can be caused by sliding the film over surfaces, creating an electrical discharge of static electricity, particularly under very dry atmospheric conditions. Half-moon- shaped marks (either dark or light) can be caused by crimping the film, particularly with the thumb. These are often referred to as thumb crimps, handle X-ray film as if it were a piece of wet paper. Scratching of the emulsion when the film is wet and the emulsion is soft is a common artifact. 6.7.19.3 Exposure Artifacts. The most common exposure artifacts are caused by excessive pressure applied to the film before, during, or after exposure. Either heavy parts or excessive bending of the film can apply sufficient pressures to the film emulsion as to render it insensitive to exposure. These artifacts usually appear as unexposed areas on the film. 6.7.19.4 Manufacturing Artifacts. Artifacts due to the manufacturing process are comparatively rare. On occasion exposed spots or other manufacturing artifacts, such as roller marks or foreign material may occur on the emulsion surface. Table 6-18 lists artifacts which are commonly encountered, their cause, and any remedial action which may be taken.

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