Questions and Answers
What is the replenishment rate of the fixer for every 35 cm or 14 in of film?
Which component acts slowly but is responsible for the very blackest shades?
Which of the following terms is NOT used interchangeably in reference to the fixing agent?
Which component helps remove principal impurities, specifically aluminum ions, during fixing?
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What are the two chemicals that work synergistically to shape the characteristic curve of a radiograph?
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What is the stage of processing that neutralizes the residual developer in the emulsion?
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Which chemical provides electrons to change the silver ion to silver?
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What term refers to the permanence of the radiograph, ensuring that the image does not deteriorate with age?
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What is the usual cause when films that drop from the processor are damp?
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Which fixing component helps to maintain proper pH in the fixer?
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What does the term hypo retention refer to?
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Which stage of processing removes excess chemicals from the film after previous steps?
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What accelerates the oxidation of hydroquinone, making the developer unstable?
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What is the principal action of the developer?
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Which developer component enhances the action of the developing agent by producing alkalinity?
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What reaction leads to the production of electrons?
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Which component is introduced into the chemistry when mixed, handled, and stored?
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What is the role of a hardener in the fixing process?
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What is the term for the phenomenon where two agents working together produce a greater effect than individually?
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What is the minimum flow rate for the wash tank in most processors?
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Which fixing component helps maintain chemical balance due to the carryover of developer and fixer?
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Study Notes
Chemical Processing in Radiography
- Stop Bath: Neutralizes residual developer in film; halts its action using an acid solution.
- Drying: Prepares radiograph for viewing by removing water.
- Reduction: Process where a chemical donates an electron to neutralize a positive ion (e.g., Ag+ + e = Ag).
- Developer: Provides electrons to convert silver ions to metallic silver.
- Hydroquinone: Controls the shoulder of the characteristic curve, influencing the image's contrast.
- Developing Stage: Converts latent images into visible images through chemical reaction.
- Depletion of Developer Hardener: Common cause for damp films dropping from the processor.
- Archival Quality: Refers to the durability of radiographs that remain unchanged over time.
- Washing Stage: Removes excess chemicals from previous processing to ensure image integrity.
- Metallic Impurities & Soluble Salts: Can accelerate hydroquinone oxidation, destabilizing developer solutions.
- Fixing Stage: Clears unexposed silver halide crystals and hardens emulsion for image preservation.
- Phenidone: Acts quickly, influencing lighter shades of gray in the image.
- Hardener: Speeds up emulsion shrinking, contributing to rigidity.
- Inadequate Washing: Main cause of excessive hypo retention in radiographs.
- Wetting Stage: Allows water to penetrate and swell gelatin in the emulsion.
- Synergism: Occurs when two agents' combined effect is greater than their individual actions.
- Oxidation: Reaction producing electrons, crucial for the photographic process.
- Water: Universal solvent, vital for various chemical processes in radiography.
- Buffer: Maintains pH balance in fixer solutions, essential for consistent processing results.
- Hypo Retention: Undesirable retention of fixer chemicals in emulsion can lead to image degradation.
- Preservative: Controls aerial oxidation of developing agents, maintaining effective development rates.
- Close-Fitting Floating Lids: Used to minimize aerial oxidation in replenishment tanks.
- Sodium Hydroxide: Strong alkaline substance commonly known as lye, used in developers.
- Silver Sulfide Stain: The most common cause of poor archival quality in radiographs.
- Transport Roller Size: Typically measures 25 mm (1 inch) to ensure proper film movement.
- Minimum Flow Rate: Wash tank flow should be at least 12 L/min (3 gal/min) for effective washing.
- Sequestering Agent: Removes metallic impurities to stabilize the developer solution.
- Chemical Fog: Type of fog caused by reduction of unexposed SHC to metallic silver.
- Replenishment Rates: Developer: 60-70 mL per 35 cm (14 in); Fixer: 100-110 mL per 35 cm (14 in).
- Transport System: Initial point where film enters the automatic processor in a darkroom.
Terminology and Components
- Fixing Agent: Interchangeable terms include hypo, clearing agent, and thiosulfate.
- Principal Components of Automatic Processor: Include transport system, temperature control system, circulation system, replenishment system, and dryer system.
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Description
Test your knowledge about the essential chemical processes in photography. This quiz covers critical stages such as stop bath, drying, and reduction. Delve into the role of various chemicals like developers in film processing.
