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Unit 3
What is the purpose of radiographic film processing? | Convert the latent image into a manifest image |
What creates the latent image? | Exposure of the silver Bromide crystals in the film emulsion by light or x-ray photons |
What transforms the image into a permanent image? | Chemical Processing |
What are the 4 stages of processing a radiograph? | Developing,fixing,washing & drying |
What is the primary function of the developing stage? | Convert the latent image into a manifest, or visible image |
What is the purpose of the developing or reducing agents? | Reduce the exposed silver Halide to metallic silver & to add electrons to the exposed silver halide |
What 2 chemicals are used to reduce the exposed silver halide to metallic silver? | phenidone & Hydroquinone |
Which chemical used to reduce the exposed silver halide is the fast reducer? | Phenidone |
Which chemical used to reduce the exposed silver halide is the slow reducer? | Hydroquinone |
What chemical is responsible for creating the lower densities on a radiograph? | Phenidone |
What chemical is responsible for creating the higher densities on a radiograph? | Hydroquinone |
What happens to the Silver Halide when Bromide & Iodide ions are removed from the emulsion? | it is reduced to Metalic Silver |
What are the primary functions of the fixing stage? | remove unexposed silver halide from the film and to make the remaining image permanent |
What are the 2 secondary functions of the fixing stage? | Stop the development process & harden the emulsion further |
What is the purpose of the fixing agent? | clear undeveloped silver halide from the film |
What type of pH does the fixer solution need to be? | Acidic |
What is the purpose of the Washing Process? | Remove fixing Solution from the surface of the film |
What happens if the film is not properly washed? | The radiograph will show a brown stain |
What causes the brown stain on the radiograph if the image is not properly washed? | Thiosulfate (fixing agent) remaining in the emulsion |
What is the process by which washing works called? | Diffusion |
How does diffusion work? | it exposes the film to water that contains less thiosulfate than the film. Since the film contains more fixing agent than the water the fixing agent diffuses into the water |
What is the purpose of drying films? | to remove 85-90% of the moisture of the film so it can be handled easily & stored while maintaining the quality of the diagnostic image |
How much moisture should finished radiographs retain? | 10-15% |
What can excessive drying of the radiograph cause? | Emulsion layers to crack |
What is the flat metal surface with an edge on either side that permits the film to enter the processor? | Feed Tray |
What rollers make sure the film is moved into and through the tanks at a constant speed? | Transport & Crossover |
What is the name of the electrical circut that shuts off power to the roller assembly when the processor is not being used? | Standby control |
What is the name for the replacement of fresh chemicals after the loss of chemicals during processing? | Replenishment |
What causes developing solution to become exhausted? | use & exposure to air |
What causes fixer solution to become exhausted? | use resulting from accumulations of silver halide that are removed from the film during the fixing process, developer solution that remains in the film |
is more fixer or development solution replaced per film? | fixer |
What is the name of the system that circulates the solutions in the tank by pumping solution out of one portion of the tank and returning it to a different location in the same tank? | Recirculation System |
How does the recirculation system help? | keeps chemicals mixed,maintains solution activity,provides agitation of the chemicals to facilitate fast processing, maintains proper temperature of the developer |
What is the developer temperature in most 90 second automatic processors? | 93-95 degrees F (33.8-35 degreese C) |
What is the name of the heating coil that is immersed in the bottom of the developer tank? | Immersion Heater |
How is the air forced through the dryer? | Blower |
How is air directed onto the film? | Air Tubes |
How should film boxes be stored? | Vertically |
What are common hazardsto radiographic quality that can be found in the darkroom? | white light exposure,safelight exposure & ionizing radiation exposure, heat, chemical exposure |
What temperature should film be stored at? | 55-75 degrees F (14-24 degrees C) |
What humidity should film be stored at? | 30-60% |
What happens to the film when stored in low humidity? | Static buildup which can expose the film |
What are some common safelight filters? | Kodak wratten 6B & Kodax GbX |
What type of film is the Kodak Wratten 6 B sesitive to? | blue-sensitive film |
What type of film is the Kodax GBX sensitive to? | ortochromatic, blue violet and green visible light |
What is the power rating of the light bulbs used in safelights? | 7.5-15W |
What term refers to the removal of silver from the used fixer solution? | Silver Recovery |
Where are the silver recovery units connected? | Drain system of the silver tank |
What are the 2 methodes of silver recovery? | metallic replacement & Electrolytic Method |
What are the 2 types of metallic replacement silver recovery units? | Steel wool & Silver-exraction filter |
What does the steel wool extraction unit use to filter the fixer solution? | Steel Wool |
How does the steel Wool extraction unit work? | Silver replaces the iron in the steel wool and is removed after significant qccumulation in a canister or replacement cartilage |
What does the silver extraction unit use to filter the fixer solution? | foam filter impregnated with steel wool |
Is the steel wool or silver extraction unit more efficient? | silver extraction unti |
What method of silver recovery is most efficient? | Electrolytic |
How doe sthe electrolytic method of silver recovery work? | They contain an electrically charged drum or disk that attracts silver |
What is another name for chemical development of the film image? | Reduction |
Under what circumstances would unexposed crystals be reduced to black metallic silver? | developer too hot or too strong |
During reduction are electrons added or given up? | Added |
What image qualities does fil processing affect? | Density, Contrast & Fog |
What are the wet porcessing factors that affect image quality? | time in developer, Temp of developer & Chemistry of the developer |
What is the normal development time? | 90-120 seconds |
Which step in chemical processing is the longest? | Drying |
What is the first and deepest tank in the processor? | Developer |
What controls the development time? | Transport rate |
What type of rollers are ribbed? | Entrance |
Arfe all entrance rollers ribbed? | no |
What triggers new chemicals? | Film going through the entrance roller |
What are rollers made of? | Hard rubber or phenolic |
Where are deep roller racks used? | developer,fixer & wash tanks |
What rollers transport film to the bottom of the tank? | Planetary or transport |
How big are the planetary & transport rollers? | 1" diameter |
What roller turns the film 180 degrees and is located at the bottom of the roller rack | Master or solar |
What helps direct the film to turn? | Guide shoes |
What type of rollers squeeze fliud from the film? | Squeegee Rollers |
Where are the Squeegee rollers located? | top of roller rack on top of each tank |
Where are the crossover racks? | on top of each tank |
What type of roller is located at the top of each tank and turns the film 180 degrees into the next deep rolller rack? | Crosssover |
What type of rollers transposrt film through the dryer? | Dryer rollers |
How are rollers connected? | Belt & Pully, Chain and Sprocket or gears |
What is the recommended temp for a 3-4 min processor? | 84-86 degrees F |
How often should you drain processing tanks? | Once a month |
What is the name of the switch that triggers the replenishment pumps? | Micro-switch |
What does film do to the fixer when it enters into the fixer tank? | Neutralizes it |
What side of the film should be placed against the feed tray guide | Short side |
what is the temperature on the dryer? | 120 degrees F |
What should be done to the processor daily? | clean crossover racks,check development temp,check wash water temp,check replenishment rates,sensitometry, crack lid at the end of the night |
Why do you crack the processor lid at the end of the night? | to avoid chemical contamination |
What should be done to the processor weekely or monthly? | Drain and clean tanks and deep racks,check belts, lubricate |
What causes insufficient processing? | Contaminated developer,insufficient developer or exhausted developer |
What happens to the film if it is stored in a place where the humidity is too high? | Fog |
What happens when you use expired film? | Age fog |
what type of marks are produced by rough handling of film? | Dark crescent marks |
What type of marks are produced by fingerprints? | minus density |
What are the 3 types of static marks? | Tree,Crown & Smudge |
what type of safelight filter is used with calcium tungstate? | Wratten 6B (amber) or GBX (red) |
What type of filter is used for rare earth? | GBX |
Orthochromatic fils produce what type of light? | Green Blue |
Is it ok to use Wratten 6B with Rare earth, orthochromatic films? | NO |
How often should you check the safelight? | Twice a year |
What are the 2 types of Dry printers? | Thermographic & Photothermographic |
Which type of dry printer uses heat to directly produce a visible image? | Thermographic |
Which type of dry printer uses a laser to form the latent image and heat to process it? | Photothermographic |
what processor artifact causes dark bands of density crosswise to the film travel? | Hesitation Marks |
What type of processor artifact causes dark densities repeated at regular intervals? | pi Lines |
What type of mark is left by emulsion pickoff? | Opaque |
What causes emulsion pickoff? | Emulsion too soft (insufficient hardner) |
Artifact: Pink stain | Exhausted fixer |
Artifact: yellow brown stain | insufficient rinsing or fixer |
What processor artifact causes clear white lines parallel to film travel? | Guide shoe scratches |
What causes guide shoe scratches? | soft emulsion being scratched,misalignment of guide shoes, dryer tubes or roller racks |
What causes hesitation marks? | pauses in transport of film through processor |
What causes pauses in transport of film through the processor? | broken gears,drive chains,transport motor failure,misalignment of guide shoes, loss of power |
Artifact: dark marks produced by friction | Static |
T or F: A wrattne 6B filter cannot be used with film sensitive to green light | True |
What does overdevelopment do to contrast, fog and density? | decrease contrast, increase fog and density |
What does underdevelopment do to contrast, fog and density? | Decrease all of them |
What are the 3 types of maintenance programs that should be included in QC for an automatic processor? | Scheduled maintenance,Preventative maintenance & Non scheduled |
What component in the developer helps swell gelatin,produces alkalinity & controls pH? | Activator |
What component in the developer works as a antifog agent and protects unexposed crystals from chemical attack? | Restrainer |
What component in the developer controls oxidation and maintains balance among the developer components? | Preservative |
What component in the developer controls emulsion swelling and enhances archival quality? | Hardner |
What component in the developer removes metallic impurities and stabilizes the developing agent? | Sequestering agent |
What component in the developer dissolves chemicals for use? | Solvent |
what is it produced when unexposed crystals are reduced to metallic silver? | Development Fog |
What do the close fitting floating lids on replenishment tanks prevent? | Aerial Oxidation |
What color does the developing agent turn when it has been oxidized? | brownish |
What is the usual cause when films drop from the processor and are still wet? | Depletion of the hardner |
What component in the fixer neutralizes the developer and stops its action? | Activator |
What component in the fixer removes the undeveloped silver bromide from emulsion? | Fixing agent |
What component in the fixer stiffens and shrinks the emulsion? | Hardner |
What component in the fixer maintains chemical balance? | preservative |
What component in the fixer maintains proper pH | Buffer |
What component in the fixer removes aluminum ions? | Sequestering Agent |
What component in the fixer dissolves other components? | Solvent |
what are some terms used for fixing agent? | Clearing agent,hypo & thiosulfate |
undesirable retention of fixer in the emulsion | Hypo retention |
What is the ph of the fixer? | acidic |
what should the temp of the wash water be? | 5 degrees F below the developer |
What does the turmaround assembly consist of? | master roller,planetary rollers & Guide shoes |
What processing stage remove the unexposed and undeveloped silver halides from the emulsion?
FIXING. The acidic fixing solution removes the unexposed and undeveloped silver bromide crystals from the film emulsion and re-hardens the emulsion that has softened during the development process.
During which step of automatic film processing are the unexposed silver halide crystals removed from the film base?
Fixing - Unexposed silver halide crystals are removed by the fixing bath. The fixer dissolves only silver halide crystals, leaving the silver metal behind. Washing - The film is washed with water to remove all the processing chemicals.
What removes unexposed silver halide?
A clearing agent, also known as fixing agent, is the chemical that actually removed undeveloped silver halide crystals from the film. Sodium thiosulfate and ammonium thiosulfate are commonly used.
What is the chemical that removes the unexposed silver halide crystals on the film?
A chemical solution known as the fixer is used in the fixing process. The purpose of the fixer is to remove the unexposed, unenergized silver halide crystals from the film emulsion. The fixer hardens the film emulsion during this process. Fixation time is 10-15 minutes, double the developing time.