The Darkroom

Document Sample
The Darkroom Powered By Docstoc
					                      The Darkroom

                      LeeAnn Pack DVM
                      The Darkroom
• Everything should be keep clean
• Room should only be used as the
• Need plenty space – not bathroom
• Clean, dry, free of chemical hands
• Proper ventilation, humidity, temp
                 See the difference?
• 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
• Should be a
  minimum of 4 feet
  from the work space
• Filters can crack so
  must be checked
• Different set ups for
                      Safelight Test
• Know how to
  perform this test
• Why might we do a
  safelight test?
          Why to NOT do manual
• Labor intensive
• People cut corners and produce bad
     – Inconsistent
• Time consuming
• Maintenance
• Messy
                      The Tanks
•   Developer
•   Rinse
•   Fixer
•   Wash
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
• Place film in an appropriate sized
• Small clips in corners pull film tight
• Hook on bottom ones first
                      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
                      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
                      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
                      Wash It
• Need 10 water changes per hour
• Film remains in wash for 15-20 minutes
• Removes excess fixer
                      Dry It
• Room temperature or in a dryer
     – Dryer will be quicker
• Excess drying can cause cracking of the
• Do not allow to touch during drying
• Cut off the nipples from the clips
• Ready for storage
             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
                      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
               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
• 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
     – Info. gets stamped onto the film with little flash of
       light into the film emulsion
                      Film Storage
                            •   Organized manner
                            •   Labeling
                            •   Envelopes
                            •   Color coded
                            •   numbered
                      Film Artifacts
• Not part of the animal being
     – 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
• Rapidly pulling film
  from box or cassette
• Low humidity –
  worse in winter
     – Should be 50-60%
• Wool clothing
• Screen cleaner
• Trees, lightening
• Chemical fog
• Light fog
     – Light leaks
     – Safelight crack
• Scatter fog
     – Film left in room
• Storage fog
     – Outdated film
     – Darkroom temp high
             Increased film density
                 Film too black
            Decreased film density
                Film too light
    Localized area of increased
            film density
   Localized area of decreased
           film density
           Distorted, Magnified, or
               Blurred Images
                Loss of film contrast
                   grey images
                Uneven film density
                      Film Discoloration
                      Tank Levels