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Film Handling Artifacts

Film Crimps

Film Artifacts, such as crimps, can appear as cracks or other defects on the film. To better understand how they look on the film perform the following exercise.

  1. When loading a piece of film, make a pronounced bend or crimp in the film.
  2. Produce a radiograph with a density between 2.0 and 3.0 of a sample part.
  3. When removing the exposed film from the cassette for developing, make a second bend or crimp in the film some distance from the first. Make sure that you can distinguish between the before exposure artifact and the after exposure artifact.
  4. Develop the film and examine the radiograph.
  5. Note the differences in the two crimps. Which of the crimps appear more like a crack?

Film Exposure From Safelight

Given enough time, film can be exposed by the safelight in the darkroom. In this example use a class 2 film, as it will more readily demonstrate the effects.

  1. After the safelights have warmed up for at least ten minutes place a opaque covering over one-half of the film. On the exposed half place lead letters, or other opaque objects. Allow the film to be exposed under the safelight for a period of fifteen minutes.
  2. Remove the opaque covering from the film while leaving the opaque letters or objects in place on the other half of the film. Allow the film to remain in the light for another fifteen minutes.
  3. Process the film and evaluate.
  4. Note the effects of the safelight on the two halves of the film.

 


NDT
Teaching Tips

Ultrasonic
Reflectors
Signal Interpretation
DAC Curve

Eddy Current
Depth of Penetration
Lenz Law

X-ray
Backscatter Radiation
Film Handling Artifacts
Focal Spot Size
Lead Screens
Source/Object Orientation