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what is optimal temperature for hand developing a radiograph
68*F or 20*C
converts latent image to visible image (converts exposed silver halide to elemental silver )
what happens to exposed silver halide during developing
turns to black metallic silver
increase the activity of the developer by causing the emulsion layer to swell and soften
prevent rapid oxidation thats associated with alkaline developers
limits the developing agent to the exposed crystals
used in automatic processors to prevent excessive emulsion swelling
dissolve the chemicals
why to we rinse radiographs
to prevent carryover contamination to fixer; developer - alkaline
fixer - acid
how long is a radiograph rinsed for
30 sec in circulating water
what happens to a film that is not fixed properly
film will discolor and darken with exposure to light
what dose fixing a radiograph do
removes unexposed silver halide from film, hardens the gelatin coating
why is rinse not used in automatic processor?
the rollers remove excess developer before it reaches the fixer
dissolves and removes unexposed silver halide crystals from the film emulsion layer; changes the apperance of radiograph to clear (trasparent) look except the black metalic silver portions remain the same
prevent decomposition of fixing agent
prevent swelling of emulsion layer and thus shortens drying time (prevents film from becoming water logged
neutralize any alkaline developer from developing solution
accelerates the action of other chemicals in the fix solution
chemical compounds used to maintain the desired PH
water-carries the silver halide away from the film
what temp is fixing done?
how long do we leave in fixer ?
10 min - rule of thumb is double the developing time ! (5 min )
how long is it left in developer ?
final wash -
to remove all the processing chemicals from film; water temp - 60 -70* F ;time- 30 min with periodic agitation
what are advantages to automatic processor?
produces a dry radiograph quickly; and reduces variables