8.1 Film Processing Part 2 Flashcards
is the first step in wet processing a film
Developing
At this stage silver is
deposited at the latent image sites and an image becomes visible
Developing
The primary agents of the developer are two ______ agents, although
automatic radiographic developer solutions also include an activator,
restrainer, preservative, hardener, and water as a solvent
reducing
Developer time in 90-sec Processor
20-25 sec
The action of the ______ is controlled by the immersion time, solution
temperature, and chemical activity
developer
provide electrons to the silver ions attached to the
sensitivity specks of the silver halide crystals (the latent image)
Reducing agents
Silver halides have negative exteriors (where bromine and iodine ions are located) and positive interiors (where silver ions are located). This
arrangement effectively prohibits the _____ agent from supplying
electrons to the silver ions because the bromine and iodine repel electrons
reducing
reduces latent image to visible black metallic silver
Developer
rapidly produces fine detail shades of gray (Developer)
Phenidone (Reducing Agent)
slowly produces heavy densities
Hydroquinone (Reducing Agent)
produces alkaline pH, swells gelatin (Developer)
Sodium carbonate (Activator)
decreases reducing agent activity, antifogging agent (Developer)
Potassium bromide (Restainer)
controls oxidation, buffer agent (Developer)
Sodium sulfite (Preservative)
hardens emulsion, reduces gelatin swelling (Developer)
Glutaraldehyde (Hardener)
dissolves chemicals for use (Developer)
Water (Solvent)
However, when a sensitivity speck has attracted silver ions, a gate exists through which
the interior of the crystal can be supplied with electrons. When a silver ion obtains an
extra electron, it is converted to a stable black metallic silver atom. _____ is
actually the process of the reducing agents giving up electrons to neutralize the positive
silver ions
Reduction
The secret to the production of the various densities is that the sensitivity speck gate
will be larger when more silver ions are deposited at the speck during exposure. A
larger gate permits ____ reduction of the internal silver atoms. When the reduction
process is stopped at the appropriate time, the silver halides have accumulated black
metallic silver in proportion to the size of the sensitivity speck gate
faster
is used to describe development when these factors
cause unexposed silver halides to be reduced
chemical fog
Those silver halide crystals that have fewer than ____ silver atoms on their
sensitivity specks are unable to open a gate and remain unreduced
(undeveloped).
three
Each reduced silver atom is accompanied by a liberated bromine ion with a
_____ charge. A bromide ion barrier is created when too many liberated
bromine ions are permitted to accumulate. They may produce sufficient
charge to repel reducing agents and effectively stop silver halide
development
negative
known as P developer
phenidone
known as Q
developer
hydroquinone
quickly reduces silver, enhancing fine detail and
subtle shades of gray, and works only in areas of light exposure
phenidone
replaces the function of metol (often known by the Kodak brand
name Elon) in manual processing
phenidone
slowly reduces silver and produces heavy density
Hydroquinone
When the two reducing agents are combined, forming a PQ
developer, their reducing ability is greater than the sum of their
independent abilities. This is a synergistic phenomenon known as
______
superadditivity
are opposite processes
Oxidation and reduction
X loses electrons,
X is oxidized by Y (becomes more positive)
Reducing agent
Y gains electrons,
Y is reduced by X (becomes more negative)
Oxidizing agent
reduces the strength of the developer
solution
oxidation/reduction process
As developer _____, it changes color, first to a deep amber, then
to brown, and, finally, to a thick, rust red
oxidizes
The action of the reducing agents is enhanced by maintaining the developer
solution in an alkaline state (around pH 10.0–10.5) by using an
_____, usually _____
activator,
sodium carbonate
may also be used as an activator
Potassium carbonate, sodium hydroxide, and potassium hydroxide
also assists the reducers in reaching the silver
halides by causing the gelatin to swell and become more permeable
activator
is caustic, and therefore rubber gloves and an apron should be
worn when handling developer solutions
activator
s also added to the developer to
restrict the reducing action to those crystals with sensitivity speck gates
restrainer, usually potassium bromide
is used as a preservative agent to help decrease the
oxidation of the reducing agents when they are combined with air
Sodium sulfite
is the most common developer solution hardener. It controls
the swelling of the gelatin to prevent scratches and abrasions to the
emulsion during processing
Glutaraldehyde
It also maintains uniform film thickness to assist in transport through an
automatic processor
Glutaraldehyde
Excessive _____ may cause the emulsion to harden prematurely,
preventing chemical interactions with the silver halides and trapping
moisture in the gelatin
hardener
The chemicals are suspended in water as a ____
solvent
The water used for
mixing chemistry should be filtered to remove impurities (a _____ filter is recommended).
5–10 μm
is the only solution that is dramatically affected by
contamination
Developer
Only ___ percent fixer in a developer tank will destroy the
ability of the reducing agents (10 ml in a 2.5 gallon [10 liter] tank).
0.1
Films processed in contaminated developer appear extremely ____ (they
exhibit extremely low contrast).
gray
requires total dumping, washing, refilling, and
seasoning of the developer tank. When cleaning a processor, the fixer tank
should always be filled first.
Developer contamination
Evaporation of solutions can also cause _____. Due to the heat
necessary for processing, solutions evaporate and condense on the
processor lid.
contamination
To prevent contamination, the processor lid should be propped ____
whenever the processor is not in use. Splashing or evaporation of developer
into the fixer tank does not cause contamination
open
If a film is exposed to light ____ development, the unreduced silver halides
will open gates and be converted to black metallic silver. This is seen as a slow blackening of the film, which obscures the image
after
Undeveloped silver halides must be removed from the emulsion to
permanently ___ the image before exposure to light for viewing
fix
This important step in fixing is accomplished by using a clearing agent that bonds
with the unexposed silver halides and removes them from the emulsion.
The primary agent of the fixer is the ____ agent, although automatic
radiographic fixer solutions also include an activator, preservative,
hardener, and water as a solvent
clearing
Fixer time in 90-sec processor
20 sec
stops reduction and removes undeveloped silver halides
from emulsion
Fixer
removes undeveloped silver halides from emulsion (Fixer)
ammonium thiosulfate (clearing agent)
provides acidic pH, stops reduction (Fixer)
acetic acid (activator)
hardens emulsion (Fixer)
potassium alum (hardener)
maintains pH (Fixer)
sodium sulfite (preservative)
dissolves chemicals (Fixer)
water (solvent)
Wash time in 90-sec processor
20 sec
removes excess chemicals (Wash)
water (solvent)
Dry time in 90-sec processor
20-30 sec
removes developing and fixing chemicals
Wash
removes water and seals emulsion
Dry
evaporates water and hardens emulsion
hot air
Nearly all fixer solutions use _____ as the clearing (fixing)
agent (also known by the term “hypo”)
ammonium thiosulfate
uses silver in the emulsion to form ammonium
thiosilversulfate. Within 5–10 seconds after the clearing agent has begun
to function, the film can be exposed to full room light for inspection without
damage to the image
ammonium thiosulfate
If the fixer has not completely cleared the film of unexposed silver halides,
the film will have a _____ appearance. The clearing time is defined as twice
the time necessary for the milky appearance to disappear
milky
In a 90-second automatic processor, the clearing time is usually _____, whereas manual processing may take _____
15–20 seconds,
2–3 minutes
is used as the activator in the fixer. It maintains an acidic pH
(4.0–4.5) to enhance the functioning of the clearing agent
Acetic acid
It also serves as a stop bath to keep the reducing agents from continuing to function when the film is immersed in the fixer
Acetic acid
Recall that reducing agents function in an alkaline solution. An acidic solution will _____ and thereby stop the alkaline developing solution
from continuing its reduction of the silver halides
neutralize
The fixer uses the same preservative as the developer-
sodium sulfite
It dissolves silver from the ammonium thiosilversulfate, thus permitting it to
continue to remove silver from the emulsion
Preservative
The hardener in the fixer must function in an ___ environment
acidic
is effective only in an alkaline solution, so fixer hardeners
are aluminum chloride, chromium alum, or potassium alum.
Glutaraldehyde
The _____ serves the same purpose as glutaraldehyde in the
developer—prevention of scratches and abrasions to the emulsion during
processing and maintenance of a uniform thickness of the film during
transport
hardener
should be filtered and treated
Water
After a time, the fixer solution will become saturated with silver ions from
the emulsion. The solution slowly becomes unable to accept additional
silver and requires a longer clearing time
Depletion
The archiving process is composed of two steps:
washing and drying
prepares the film for long-term storage as a medical record by
protecting it from deterioration by chemicals, fading, and physical forces
Archiving
uses water to remove as much of the fixer and
developer solutions as possible
washing process
The water temperature in washing should be slightly ____ than the temperature of the
other solutions _____ because some processors use the
water to help control temperature fluctuations in the developer and fixer
lower,
about 5°F or 3°C lower
Both fixer and developer solutions contain chemicals that, even in _____
concentrations, can damage the image over time. Because most of the
developer action is stopped by the acidic pH of the fixer, the main concern
is removing the fixer from the emulsion
weak
will increase the efficiency of the wash
Warm water
especially those not made of stainless steel, are susceptible to algae and
bacteria growth during periods when the processor is turned off
Wash tanks
is done by forcing hot air over both sides of the film as it begins its
exit from the processor
Drying
Drying temperature
ranges from 120–150°F (43–65°C)
Proper storage is a critical part of the archiving process. The length of time
an original radiograph is stored is usually ___, depending on
institutional policies and applicable laws
5–7 years
Processed radiographs should be stored at about _____ and
_____ humidity
70°F (23°C),
60 percent
THE AUTOMATIC PROCESSOR
Main systems are:
- ) Transport system
- ) Temperature control system
- ) Recirculation system
- ) Replenishment system
- ) Dryer system
- ) Electrical system
When the radiographic film is advanced slightly while on the
feed tray, ____ grab the film and draw it into the
developer tank
entrance rollers
The entrance rollers separate slightly as the film passes
between them activating a _____ that controls the
replenishment of the processing chemicals
microswitch
When the film completely passes through the entrance rollers
and into the developer tank, the microswitch disengages and
the safelight is turned ___, indicating it is safe to open the
darkroom door
on
Single films should be placed ______ (the film’s short axis is
parallel to the side rails of the feed tray) whenever possible,
that is, only if the transversely placed film can lie flat between
the side rails of the tray as it is fed into the automatic processor
transversely
carries the radiographic film
through the developer, the fixer, the washer, the dryer
and finally into the receiving bin
transport system
The SUBSYSTEMS of the transport system are:
rollers,
transport racks and drive motor
positioned along the front and back
portions of the transport racks, are 1 inch in diameter and
are either positioned directly across from each other or
offset
Transport rollers
These rollers propel the film down and up through the
transport racks of each processor tank
Transport rollers
Positioned at the bottom of each transport rack is a
turnaround assembly
It contains a 3 inches master, or solar roller surrounded
by planetary rollers
turnaround assembly
