Week 6 D1. Ch8&10 Digital. Film Process. Flashcards
MANUAL FILM PROCESSING
DEVELOPMENT
Initiates the chemical reaction that reduces exposed silver halide crystals into black metallic silver creating dark or black areas on a radiograph; emulsion is softened
RINSING
The film is rinsed removing any remaining developer solution and arresting the developing process
FIXATION
Removes unexposed silver halide crystals creating white or clear areas on a radiograph; emulsion is hardened
WASHING
Remaining chemical solutions are removed in water bath
DRYING
FILM PROCESSING SOLUTIONS
• Fresh chemicals produce the best radiographs
• Film processing solutions should be replenished daily and changed every 3-4 weeks to maintain freshness.
• Follow the dental office’s protocol regarding film processing solutions
and maintenance
DEVELOPER COMPOSITION
DEVELOPING / REDUCING AGENT
• optimum temperature is 68 degrees F
• Hydroquinone
• converts exposed silver halide crystals to black metallic silver producing black tones and contrast in the image
• Elon / Metol
• Converts exposed silver halide crystals to black metallic silver producing many shades of gray on a radiograph
PRESERVATIVE
• Sodium sulfite
• Prevents oxidation of the developing agents
DEVELOPER COMPOSITION
Accelerator
• Sodium Carbonate
• activates the developing agents
• provides alkaline environment for developing agents
• softens gelatin of the film emulsion
RESTRAINER
• Potassium bromide
• controls the developer and prevents the developer from developing unexposed silver halide crystals
• prevents fogging
FIXER COMPOSITION
FIXER COMPOSITION
FIXING / CLEARING AGENT
• Sodium thiosulfate
• Ammonium thiosulfate
• removes or clears all unexposed undeveloped silver halide crystals from the emulsion of the film
PRESERVATIVE
• Sodium sulfite
• Prevents deterioration of the fixing agent
FIXER COMPOSITION
FIXER COMPOSITION
HARDENING AGENT
• Potassium alum
• hardens and shrinks the gelatin in the film emulsion
ACIDIFIER
• Acetic acid
• Sulfuric acid
• neutralizes the alkaline developer and stops further development
• produces the necessary acidic environment required by the fixing agent
COMPONENTS OF THE AUTOMATIC
PROCESSOR
DEVELOPER COMPARTMENT
• Holds a highly concentrated developing solution
• Temperature 80-95 degrees F
FIXER COMPARTMENT
• Holds a highly concentrated fixer solution utilizing additional hardening agents
• Film is transported directly to the fixer compartment from the developer compartment without rinsing
WATER COMPARTMENT
• Holds circulating water washing the films following fixation
LIGHT FILM
• Image appears very light on a dental radiograph ie: low density
• Caused from insufficient developing time, low developer temperatures, depleted or contaminated developer solutions, inaccurate timer and thermometer
DARK FILM
• Image appears very dark on a dental radiograph ie: high density
• Caused from excessive developing time, high developing temperatures, inaccurate timer and thermometer
RETICULATION
• Caused from a sudden change between developer and water bath
temperature
• Always check the temperature of processing solutions and water bath
DEVELOPER SPOTS
• Caused from the DEVELOPER solution coming in contact with film before processing
• Always ensure a clean working area
DEVELOPER SPOTS
• Caused from the DEVELOPER solution coming in contact with the film before processing
• Always ensure a clean working area
FIXER SPOTS
• Caused from the FIXER solution coming in contact with the film prior to processing
• Always ensure a clean working area
YELLOW-BROWN STAIN
• Caused from exhausted processing solutions, insufficient fixing or rinsing
• Replace or replenish processing solutions
• Ensure film has adequate fixation and rinse times
DEVELOPER CUT-OFF
• Caused from low level of developer solution resulting in a partial image
• Caused from the films not being completely immersed in the developer solution due to clipping the films at the very top of the film rack
• Replenish developer solution when necessary and take note of film placement on film racks
FIXER CUT-OFF
the film
• Caused from the films not being completely immersed in the fixer solution due to clipping the films at the very top of the film rack
• Check fixer level prior to processing films and ensure that all films on the film rack are completely immersed in the fixer solution
OVERLAPPED FILM
• Caused when two films come in contact with each other during processing
• Films that overlap in the developer exhibit white areas representing an undeveloped portion of the film
• Films that overlap in the fixer exhibit black areas representing an unfixed portion of the film
AIR BUBBLES
• Caused when air is trapped on a film surface after being placed in the processing solutions preventing the chemicals from affecting the film emulsion in that region
• After immersing the film racks in the processing solutions, gently agitate and stir the film racks
FINGERNAIL ARTIFACT
• Caused by rough handling of the film damaging the film emulsion with operator’s fingernail
• Films should always be handled by the edges only
FINGERPRINT ARTIFACT
• Caused from touching the film with contaminated fingers of developer or fluoride
• Prior to processing films, wash and dry hands thoroughly
• Work in a clean area
STATIC ELECTRICITY
• Caused from opening a film packet too quickly or opening a film packet prior to touching another object eg: touching a countertop in a carpeted area
• Ensure that film packets are opened slowly
SCRATCHED FILM
• Caused when the film emulsion is removed from the base by a film clip or hanger
• Use care when placing a film rack in the processing solutions avoiding contact with other film hangers
FOGGED FILM
• Caused from improper safe lighting and light leaks in the darkroom and film storage, contaminated processing solutions or high developer temperature as well as expired films
• Check the bulb wattage of the safelight and the darkroom for light leaks
• Store films in a cool, dry area; note expiration date
LIGHT LEAK
• Caused from white light exposure or defective film packets
• Never unwrap films in the presence of white light and check the packets for any minute tears or defects
