Radiographic Film

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Radiographic Film
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Film Types

• Direct exposure
• Screen type

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Direct exposure film

• Radiographic film was contained within a light
  tight cardboard holder. The radiation directly
  exposed the film.
• Radiographic techniques were 10 to 100 times
  greater than with todays technology.
• Great detail was obtained with this film type

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Screen type film

• A double emulsion film which is utilized is very
  light sensitive.
• Housed inside a cassette which has intensifying
  screens on either side of the film.
• Utilizes far less exposure for the same
  radiographic anatomy.

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Composition of radiographic film

• Base or support
• Emulsion
• Gelatin
• Silver halide
• Overcoat

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Base or support

• Provides the appropriate degree of strength,
  stiffness, and flatness for handling and good
  dimensional stability.
• Composed of blue tinted transparent plastic.

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Emulsion

• Made up of gelatin which encases silver halide
  crystals.
• The gelatin allows for even dispersement of the
  silver halide crystals and is easily penetrated
  by the fixer and developer solutions.

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Overcoat

• A protective material that is over the emulsion
  that lessens the possibility of damage to the
  films sensitive surface.
• It also allows the film to be transported through
  film changers without damage.

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Latent image formation

• Exposure of the film to light or x-rays causes
  the silver halide crystals to become negatively
  charged.
• This negative charge allows the crystal to become
  clumped together.
• When exposed to the developer, these clumps turn
  into the black that we view on the radiograph.
• When exposed to fixer, the unexposed crystals are
  removed which gives the clear areas on the
  radiograph.

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Silver halide crystals

• Specks of silver which have been combined with
  the halide family of elements bromide, chlorine
  or iodine.
• These micro crystals are very sensitive to x-rays
  or light.
• When exposed to developer, reduction takes place
  in which the crystals are converted to tiny
  masses of black metallic silver, leaving
  unexposed crystals unaffected.

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Thats All Folks