Chapter 9: Film processing Flashcards
a series of steps that produce a visible permanent image on a dental radiograph.
film processing
The purpose of film processing is twofold, as follows:
- CONVERT latent image into a visible image
2. PRESERVE visible image so that it is permanent
this absorbs x-radiation during x-ray exposure and store the energy from the radiation
silver halide crystals
latent image
stored energy on the exposed film that cannot be seen until processed
when the halide portion of the exposed, energized silver halide crystal is removed. This is called :
reduction
this initiates a chemical reaction that REDUCES the exposed silver halide crystals into black metallic silver and creates dark or black areas on a dental radiograph
developer solution
REMOVES the unexposed silver halide crystals and creates white or clear areas on the dental radiograph.
fixer solution
this structure is one that readily permits the passage of the x-ray beam and allows more x-rays to reach the film.
radiolucent
this structure is one that resists the passage of the x-ray beam and restricts or limits the amount of x-rays that reach the film.
radiopaque
two types of film processing techniques
manual
automatic
Automatic film processing consists of the following four steps:
development
fixing
washing
drying
light-shielded compartments, that can be used in a room with white light
daylight loader
Automatic processing is preferred by many dentists as a method of film processing for the following reasons:
less processing time
time and temp automatically controlled
less equipment is used
less space is required.
encases all the component parts of the automatic processor.
processor housing
an opening on the outside of the processor housing used to insert unwrapped films into the automatic processor.
film feed slot
is a system of rollers used to move the film rapidly through the developer, fixer, water, and drying compartments.
roller film transporter
holds heated air and is used to dry the wet film.
drying chamber
used to maintain proper solution concentration and levels
replenisher pump and replenishing solutions
an opening on the outside of the processor housing where the dry, processed radiograph emerges from the automatic processor.
film recovery slot
how often should the automatic processor be cleaned
daily or weekly cleaning
what is used to clean the rollers of the automatic processor
cleaning film
Processing solutions in the automatic processor must be replaced how often?
2-6 weeks
steps of manual film processing
developing rinsing fixing washing drying
which solution softens the film emulsion ?
development
necessary to remove the developer from the film and stop the development process
rinsing
which solution hardens the film emulsion ?
fixer
The final step in manual film processing
drying
generates the black tones and the sharp contrast of the radiographic image
Hydroquinone
optimal temerapture for developer solution
68F
also known as metol, acts quickly to produce a visible radiographic image. this generates the many shades of gray seen on a dental radiograph
Elon
prevents the developer solution from oxidizing in the presence of air.
preservative (sodium sulfite)
is used in the developer solution as an accelerator.
sodium carbonate
purpose of the accelerator (also called the activator) is to :
activate developing agents
The essential piece of equipment required for manual processing is a _____
processing tank
Two removable 1-gallon insert tanks hold the developer and fixer solutions.
insert tanks
this tank suspends both insert tanks and is filled with circulating water.
master tank
a device equipped with clips used to hold films during processing
film hangers
used to agitate the developer and fixer solutions before processing.
stirring rod/ stirring paddle
Any white light that “leaks” into the darkroom (e.g., from around a door or through a vent) is termed
light leak
x-ray film is extremely sensitive to visible white light. Any leaks of white light in the darkroom cause ___ ______
film fogging
Any white light that “leaks” into the darkroom
light leak
what causes film fogging
light leaks
special type of lighting used to provide illumination in the darkroom is termed safelighting.
low-intensity light composed of long wavelengths in the red-orange portion of the visible light spectrum.
safelighting
safelight filter removes the short wavelengths in the blue-green portion of the visible light spectrum that are responsible for exposing and damaging x-ray film.
safelight filter
how far should safelight be placed
4 ft away from the film and work area
A relative humidity level of between __ and __% should be maintained
50 & 70
if the room temperature exceeds 90° F ___ ____ results
film fogging
The duplication of film requires the use of a ______ and _______ ____
film duplicator
duplicating film
the process that occurs when developer and fixer solutions combine with oxygen and lose strength, takes place when the processing solutions are exposed to air.
oxiditation
