automatic film processing

1. Automatic Film Processing Film Transport Water System Recirculation Replenishment System Developing Fixing Washing Drying There is also manual processing (processing done by the individuals) but due to the lack of consistency of people, automatic film processing is the method of choice. Automatic film processing is made up of 7 components. There is also manual processing (processing done by the individuals) but due to the lack of consistency of people, automatic film processing is the method of choice. Automatic film processing is made up of 7 components.

2. Film transport has 2 functions. The film must spend a certain amount of time in each section so that the film will be processed adequately. The motion of the system allows agitation at the film surfaces, which improves uniformity of processing.Film transport has 2 functions. The film must spend a certain amount of time in each section so that the film will be processed adequately. The motion of the system allows agitation at the film surfaces, which improves uniformity of processing.

3. Make up of the Transport System Entrance roller or detector roller Vertical or Deep racks (transport racks) Crossover assembly Squeegee assembly

4. Entrance roller or detector roller Contains the Entrance rollers and guide shoes which moves film into the developer tank Also contains a micro switch which turn on the replenishment pump

5. Vertical or Deep racks (transport racks) Moves film into and through solutions and dryer Uses a turn around assembly at the bottom of the tank to turn film direction upward.

6. Crossover assembly Moves film form developer to fixer tank and from the fixer to the wash tank Forces solutions from film back into the tank it is coming from.

7. Squeegee assembly Moves the film from the wash tank to the dryer Squeegee action removes excess water from the film.

8. Water System Washing the film Temperature control Water system has 2 functions.Some processors have hot and cold water, others have cold water only and have an internal heating system.Water must be clean and free from sludge and other components that may alter processing.Water system has 2 functions.Some processors have hot and cold water, others have cold water only and have an internal heating system.Water must be clean and free from sludge and other components that may alter processing.

9. Circulation or Recirculation or Filtration System Agitates developer solution Removes reaction particles by the use of a filtration system Helps stabilize developer temperature. Agitation and circulation Agitation keeps solutions in contact with a heater element in the bottom of the tank and prevents layering of chemicals Maintains developer temperature Heating element is controlled by a thermostat

10. Replenishment or Regeneration Systems Responsible for replenishing processor solutions that are used during processing Consist of a series of umps, plastic tubing and plastic storage tanks. Replenishment is based on the length of the film processed. Replenishment has 2 functions. Both under and over replenishment will lead to sub optimal radiographsReplenishment has 2 functions. Both under and over replenishment will lead to sub optimal radiographs

11. Types of Replenishment Volume Replenishment A volume of chemicals are replaced for each film that is processed. Flood Replenishment Periodically replenishes chemicals regardless of the number of films processed.

12. Developing Changing the latent image of film to a visible image (manifest image) composed of minute clusters of silver. Developing has one main function. There are 6 components of developing.Developing has one main function. There are 6 components of developing.

13. Components of the Developer Solvents Developing agents Accelerators Preservatives Restrainers Hardeners

14. Solvents of the Developer Water is the solvent in the developer Water dissolves and ionizes the developer chemicals Film emulsion also absorbs water, causing it to swell. This allows the dissolved developing agents to penetrate the emulsion and to reach all the silver halide crystals. Primary component of the Solvent is Water. Has 2 functions.Primary component of the Solvent is Water. Has 2 functions.

15. Developing or Reducing Agents This component oxidizes the silver and converts the latent image into the manifest image Two Components of Reducing Agents Hydroquinone - Slowly builds black tones for contrast Phenidone � quickly builds gray tones 2 agents make up the developer The main function is to convert silver to metallic silver2 agents make up the developer The main function is to convert silver to metallic silver

16. Accelerators or Activator Composed of : Sodium or potassium carbonate Sodium or potassium hydroxide Increase the rate of chemical reaction, converting exposed silver halide grains into metallic silver at a more rapid rate. Swells and softens the emulsion so that the reducing agents may work more effectively. Provides an alkaline medium for reducing agents Two accelerators 2 Functions of acceleratorTwo accelerators 2 Functions of accelerator

17. Accelerators or Activator Must have a pH of between 10 and 11.5 Must be alkaline

18. Preservatives of the Developer Sodium or potassium sulfite Help maintain the rate of development and prevent staining of the film emulsion layer Also helps protect the hydroquinone from oxidation Preservative made up of Function of preservativePreservative made up of Function of preservative

19. Restrainers or anti-foggers Potassium bromide Potassium iodide Protect unexposed silver halide grains from the action of the developer, minimizing film fog. Restrainer made up of either PB or PI Function of restrainersRestrainer made up of either PB or PI Function of restrainers

20. Hardeners of Developer Glutaraldehyde Prevents excessive swelling of the gelatin and damage to the film as it passes through the rollers. When the film enters the developer solution, the gelatin emulsion beging to soften and swell so that the chemicals can do their job. The hardener prevents for excessive swelling and prevents the emulsion from sticking to the rollers. Hardeners made up of Function of the hardenerWhen the film enters the developer solution, the gelatin emulsion beging to soften and swell so that the chemicals can do their job. The hardener prevents for excessive swelling and prevents the emulsion from sticking to the rollers. Hardeners made up of Function of the hardener

21. Fixing Clearing of undeveloped crystals before washing to prevent discoloration of the film with age or exposure to visible light. Film leaving the developer contains metallic silver grains at the sites where x-ray photons did not expose the film. Unexposed crystals are unaffected by the developer and have to be removed. The gelatin coatings must also be hardened so that the film will resist abrasion and may be dried with warm air. The fixer contains 6 agentsFilm leaving the developer contains metallic silver grains at the sites where x-ray photons did not expose the film. Unexposed crystals are unaffected by the developer and have to be removed. The gelatin coatings must also be hardened so that the film will resist abrasion and may be dried with warm air. The fixer contains 6 agents

22. Fixer Components Solvent Fixing agent Preservative Hardener Acidifier Buffer

23. Solvent of the Fixer Water Diffuses into the emulsion, carrying with it the other dissolved chemicals of the fixer. The main solvent of the fixer is Function isThe main solvent of the fixer is Function is

24. Fixing or Clearing Agent Sodium thiosulfate and ammonium thiosulfate Dissolves and removes the undeveloped silver halide grains from the emulsion. This allows the unexposed areas of the film to go from a milky-white appearance to a transparent appearance. Primary fixing agent Functions If the film is improperly fixed, the remaining unexposed silver halide crystals continue to darken upon exposure to visible light after processing has been completed.Primary fixing agent Functions If the film is improperly fixed, the remaining unexposed silver halide crystals continue to darken upon exposure to visible light after processing has been completed.

25. Preservative of the fixer Sodium sulfite Prevents decomposition of the fixer Makes the fixer able to recycle back into a fixer solution Composed of Function ofComposed of Function of

26. Hardener or Tanning Agent of the Fixer Aluminum chloride, aluminum sulfide, or potassium alum. Prevents the gelatin of the emulsion from swelling excessively. Also prevents softening by the wash water or by warm air drying. Shortens the drying time. Composed of 3 functionsComposed of 3 functions

27. Acidifier Acetic acid Accelerates the action of other chemicals Neutralize any developer that may be carried over from the developer tank. Composed of Functions of Composed of Functions of

28. Buffer Chemical compounds that maintain a constant pH of the solution during the fixing process. Maintain pH of Fixer Should be between 4 and 4.5 When high pH developer neutralizes the low pH acidic solutions of the fixer, buffers act to maintain the pH at the desired level for optimum fixing action.When high pH developer neutralizes the low pH acidic solutions of the fixer, buffers act to maintain the pH at the desired level for optimum fixing action.

29. Washing Removes the last traces of processing chemicals and prevents fading or discoloration. One of the important characteristics of a finished radiograph is its archival (long-term) storage capability.One of the important characteristics of a finished radiograph is its archival (long-term) storage capability.

30. Drying To dry the radiograph after being processed. A blower supplies heated air to the dryer section of the film processor which consist of tube like rollers. Most of the air is recirculated. The rest is vented to prevent buildup of excessive humidity in the dryer.

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