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45 Cards in this Set

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Three qualities of a dark room
clean
organized
light proof
Seven qualities of a dark room
-seperate from radiographic suite
-no less than 6-8 feet in diameter
-used for one purpose
-layout should reduce probability of film damage
-equipment located quickly and easily
-good climate control
-good ventilation
Two sides of darkrooms
dry
wet
What happens on dry side?
cassettes are loaded and reloaded
must be impossible for any chems to splash on dry side
nothing wet should ever be on dry side
film storage in a cabinet or film bin
countertops large enough for the biggest cassettes
What happens on the wet side?
-actual chemical processing occurs
-developer, wash and fixer tanks
-tanks should be free-standing
-water tank should circulating water
Film hangers
channel
clip
-used for drying during hand developing
-hangers come for each size film
Channel hangers
-retain water and chems
-need special cleaning to prevent contamination on dry side
-film has to be
removed in order to dry
Clip hangers
they are more fragile than channel hangers
clips become weak over a period of time and lose their ability to stretch
can leave punctures in film
can scratch other film in storage
cause injuries to staff
Chemical processing solutions
developer
wash
fixer
Tank construction
-3-5 gallons
-warmed by immersed heater
-thermastatically controlled water in one tank
-radiographic film has to be developed for a speicific amt of time based on the temp of chems
Wet side drying area should have a ______ for drying
rack - or a drying cabinet in dust free area
forced heat air to help drying
Viewing screen on wet side
if second radiograph is needed the error of first can be identified and corrected
Lightproofing
go into darkroom and wait for eyes to adpt - check for leaks around doors, light fixtures, walls
Lightproof doors
-dbl door or revolving door system is preferred
standard door needs to fit into it's door frame against strip of felt or rubber molding
-weatherstripping
vapor-seal
sliding lock or door knob lock
Place _______ on ceilings to prevent light leaks
large black sheet of plastic
The walls of adarkroom should have ______ colored walls bc_______
white walls - the lighter color will allow for reflection of the safelight
Safelights
light produced will not affect the film
safelight filter
-varies with manufacturere
-brown-blue senstive film
-drk red - green sensitive film
light bulb - 15 watts or less
drk red is usually recommended - both blue and green film can be used with drk red filter
Direct safelighting
diffused light that shines directly over the work area
Indirect safelighting
filtered light directed towards the ceiling and reflected over the entire room
used with direct lighting
Mounting of safelight
-no closer than 4 ft from work area
Three things that cause film fogging
-safelight mounted too close
-too high of wattage for bulb
-incorrect filtration
Efficiency of safelights need to be tested
-no light is actually safe for a long period of time
-film bin should only be opened when removing or replacing film
-fogging will result even if just safelight is on and bin is left open
Five steps to film processing
1. Developing
2. rinsing (stop bath)
3. fixing
4. washing
5. drying
Chemicals can be purchased as either_____ or ______
powders or liquids
Proper chemical temps
too low-sluggish-undeveloped rads
too high-chem activity becomes too high for manual control
All chems should be kept at the same temp to avoid_______
reticulation, which is mottling density on a finished radiograph caused by irregular expansion and contraction of the film emulsion
Quality assurance programs allows___________
reproducibility and gives radiogrpahers confidence in the exposures used on each radiograph
Developer
-converts the latent image on a film to a visible image
-converts silver srystals to black metallic silver
-time developing is specified by manufacturer and is preferred over visual inspection
Manual inspection "sight inspection"
increasing or decreasing time according to visual appearance of rads
Disadvantages of sight inspection
requires skill and attention
-many errors can occur
-should be avoided whnever possible
Developer consists of 5 things
developing agents
accelerators
preservatives
restrainers
hardeners
solvent
Developing agents
hydroquinone and phenidone
converts silver halide crystals to black metallic
-has little or no effect on unexposed silver halide crystals
Accelerators
increase the activity of the developer
increases pH
causes emulsion to swell and soften
Preservatives
-prevents rapid oxidation that can occur with alkaline developing agents
-helps maintain stable development rates
-prevents staining of the emulsion layer
restrainers
limits the action of the developing agent to the exposed silver bromide crystals in the film
hardeners
harden film during processing
prevents excessive swelling of emulsion
added to developers on automatic processors
solvent
water
Three purposes of rinse bath
1. stop developing process
2. rinse developer from film
3. prevents carry over contamination from fixer
Rinse bath
-consists of circulating water
-film rinsed for 30 seconds
-acetic acid and water(stop bath)
-rinse bath is not needed in automatic processing bc the rollers will remove the excess developer
Fixer
1. Clears the unexposed silver halide crystals from the film
2. Hardens the gelatin coating so that it can be dried without damaging the film surface
Film should be in the fixer for _______________
10 minutes
Fixer consists of 6 things:
1. clearing (fixing) agents
2. preservatives
3. hardeners
4. acidifiers
5. buffers
6. solvent
Clearing or fixing agents
-dissolves or removes the unexposed silver halide crystals
-most common agents sodium thiosulfate and ammonium thiosulfate
-changes appearance from milky white to clear
Preservatives
prevent decomposing of the fixing agent