The Darkroom

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					                      The Darkroom

                      LeeAnn Pack DVM




www.upei.ca/~vetrad
                      The Darkroom
• Everything should be keep clean
• Room should only be used as the
  darkroom
• Need plenty space – not bathroom
• Clean, dry, free of chemical hands
• Proper ventilation, humidity, temp

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                 See the difference?




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                      Safelights
• Illumination allowing people to see to
  develop film but will not cause film fog
     – Fog = unwanted blackening from light
• Films sensitive to blue light  amber
• Films sensitive to green light  red
• Filters are used with a 15 Watt bulb


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                      Safelights
• Should be a
  minimum of 4 feet
  from the work space
• Filters can crack so
  must be checked
• Different set ups for
  safelights


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                      Safelight Test
• Know how to
  perform this test
• Why might we do a
  safelight test?




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          Why to NOT do manual
               processing
• Labor intensive
• People cut corners and produce bad
  rads
     – Inconsistent
• Time consuming
• Maintenance
• Messy
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                      The Tanks
•   Developer
•   Rinse
•   Fixer
•   Wash




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Getting ready for development
• Check tank levels
     – They should completely cover the films
• Check developer tank temperature
• Stir the tanks to stir the chemicals
     – Use different stick (paddles)
• Remove film from cassette
     – Hold only by edges

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                      Then
• Place film in an appropriate sized
  hanger
• Small clips in corners pull film tight
• Hook on bottom ones first




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                      Develop It
• Silver halide crystals are reduced to
  metallic silver
• Put film in, start timer, agitate film to
  dislodge air bubbles from surface
• 5 minutes at 68 degrees F
     – Time temperature charts
     – Time and temperature are opposites

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                      Rinse It
• Removed quickly from the developer
  and do not allow to drip back into
  developer tank
• Allows for removal of excess developer
• Agitate in the rinse for 15-30 seconds
• Remove and allow to drain into rinse,
  not into fixer because it will cause fixer
  dilution
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                      Fix It
• Fix for twice development time
• Agitate to remove bubbles
• Remove and do not allow to drain back
  into fixer tank
• Fixer stops residual development
• Preserves emulsion and allows for film
  storage
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                      Wash It
• Need 10 water changes per hour
• Film remains in wash for 15-20 minutes
• Removes excess fixer




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                      Dry It
• Room temperature or in a dryer
     – Dryer will be quicker
• Excess drying can cause cracking of the
  emulsion
• Do not allow to touch during drying
• Cut off the nipples from the clips
• Ready for storage
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             Automatic Processing
• All steps of the manual process are
  mechanically performed
• Maintenance easy
• 90 seconds to 7 minutes dry to dry time
• More consistent radiographs
     – Less film artifacts
• Reasonably priced
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                      How It Works
• Built in heating element
• Feed tray feeds film into a roller system
• Roller system takes film through each tank
     – Time spent in each tank is determined by the
       settings of the gears and speed of the motor
• Ends at the dryer
• Chemicals are replenished after each film


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               Patient Identification
• Films are legal documents
• Must be in the emulsion
     – Not written on afterwards
• Hospital of Doctor name
• Patient name
• Date
     – Other info like breed, sex, age, owners
       name can be added but is not required
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• Lead impregnated tape
     – Info. written on tape and the place on cassette
• Lead identification markers
     – Make up name stick on white tape put on cassette
       – lose them they are small
• Photoprinter
     – Inside cassette, screen missing upper right hand
       corner
     – Info. gets stamped onto the film with little flash of
       light into the film emulsion
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                      Film Storage
                            •   Organized manner
                            •   Labeling
                            •   Envelopes
                            •   Color coded
                            •   numbered




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                      Film Artifacts
• Not part of the animal being
  radiographed
     – Introduced during film handling, storage,
       during the exposure or during development
• Are unwanted and do not contribute
  anything useful to the image
• They are often distracting

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                      Static
• Rapidly pulling film
  from box or cassette
• Low humidity –
  worse in winter
     – Should be 50-60%
• Wool clothing
• Screen cleaner
• Trees, lightening

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                           Fog
• Chemical fog
• Light fog
     – Light leaks
     – Safelight crack
• Scatter fog
     – Film left in room
• Storage fog
     – Outdated film
     – Darkroom temp high

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             Increased film density
                 Film too black




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            Decreased film density
                Film too light




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    Localized area of increased
            film density




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   Localized area of decreased
           film density




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           Distorted, Magnified, or
               Blurred Images




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                Loss of film contrast
                   grey images




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                Uneven film density




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                      Film Discoloration




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                      Tank Levels




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                      Misc.




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