Podcast
Questions and Answers
What is the primary role of phenidone reducer in development?
What is the primary role of phenidone reducer in development?
Which reducer is known for providing upper scale density?
Which reducer is known for providing upper scale density?
What is the function of the buffer in the developing process?
What is the function of the buffer in the developing process?
What does an activator do in the development process?
What does an activator do in the development process?
Signup and view all the answers
What is the purpose of an anti-foggant in photographic development?
What is the purpose of an anti-foggant in photographic development?
Signup and view all the answers
Which component acts to prevent rapid aerial oxidation?
Which component acts to prevent rapid aerial oxidation?
Signup and view all the answers
What does a bleacher usually contain to inhibit growth of fungi?
What does a bleacher usually contain to inhibit growth of fungi?
Signup and view all the answers
What is the role of a wetting agent in the development process?
What is the role of a wetting agent in the development process?
Signup and view all the answers
Which reducer is characterized by providing intermediate density and is sensitive to light and temperature?
Which reducer is characterized by providing intermediate density and is sensitive to light and temperature?
Signup and view all the answers
What is the main benefit of using a carbonate buffer in photographic development?
What is the main benefit of using a carbonate buffer in photographic development?
Signup and view all the answers
Which chemical is added specifically to PQ developers to enhance their function?
Which chemical is added specifically to PQ developers to enhance their function?
Signup and view all the answers
Which component functions to control the activity of the reducers in the photographic development process?
Which component functions to control the activity of the reducers in the photographic development process?
Signup and view all the answers
What role does the sodium sulfite play in photographic development?
What role does the sodium sulfite play in photographic development?
Signup and view all the answers
Which chemical is primarily used as an anti-oxidant in photographic development?
Which chemical is primarily used as an anti-oxidant in photographic development?
Signup and view all the answers
What is the primary function of a hardener in the photographic development process?
What is the primary function of a hardener in the photographic development process?
Signup and view all the answers
Which of the following is used to promote uniform development by reducing surface tension?
Which of the following is used to promote uniform development by reducing surface tension?
Signup and view all the answers
Which chemical acts as a clearing agent by dissolving unexposed silver halide crystals?
Which chemical acts as a clearing agent by dissolving unexposed silver halide crystals?
Signup and view all the answers
How does a replenisher differ from a standard developer solution?
How does a replenisher differ from a standard developer solution?
Signup and view all the answers
Study Notes
Developer Chemicals
-
Phenidone reducer:
- Builds gray tones.
- Provides intermediate density.
- Sensitive to light and temperature.
- Dmin = 1.2
-
Hydroquinone reducer:
- Builds blacks.
- Provides upper-scale density.
- Sensitive to oxygen.
- Dmax
-
Elon/Metol reducer:
- Added to hydroquinone in manual processing.
-
PQ reducer:
- Used for automatic processing.
- 15x superadditivity than MQ.
-
MQ reducer:
- Used for manual processing.
-
Carbonate buffer:
- Maintains pH.
- Source of alkali.
- Can be either Na or K carbonate.
-
Accelerator:
- Speeds up development.
- Allows the reducers to attack the AgBr crystals after swelling.
- Can be either Na or K hydroxide.
-
Activator:
- Facilitates swelling of gelatin.
-
Alkalinizer:
- Decreases and maintains the level of pH.
- Provides the necessary alkaline medium due to the hydroxide.
-
Wetting agent:
- Stimulates uniform development by reducing surface tension.
-
Restrainer:
- Prevents overdevelopment.
- Can be either K or Na bromide.
- Can also be K or Na iodide.
-
Regulator:
- Controls the activity of the reducers.
-
Anti-foggant:
- Prevents chemical fog.
-
Starter solution:
- Added only to a fresh developer solution.
-
Benzothiosulfate organic restrainer:
- Added only to PQ developers.
-
Na sulfite:
- Preservative.
- Prevents rapid aerial oxidation.
-
Cycon:
- Stabilizer.
- Promotes equilibrium of chemicals.
-
Anti-oxidant:
- Prevents rapid chemical oxidation.
- Reacts with quinone, forming hydroquinone monosulfate.
-
Glutaraldehyde:
- Hardener/tanning agent.
- A weak hardener.
- Prevents damage to the emulsion during transport.
-
Dialdehyde:
- Hardener/tanning agent.
- A weak hardener.
- Prevents damage to the emulsion during transport.
-
Distilled water:
- Solvent.
- Dilutes and concentrates chemicals for proper strength.
-
EDTA:
- Anti-sequestering agent.
- Chelates/borate salts.
- Prevents precipitation of aluminum and calcium.
- Prevents sludge formation in the bottom of the tank.
-
Calgon:
- Anti-sequestering agent.
- Chelates/borate salts.
- Prevents precipitation of aluminum and calcium.
- Prevents sludge formation in the bottom of the tank.
-
Bleach (5% fungicides):
- Inhibits the growth of fungi.
-
Anti-frothant:
- Prevents bubble formation.
- Prevents air oxidation.
-
Replenisher:
- High in reducers, activators, and preservatives but without a restrainer.
- Can return the chemical activity of the developer back to the original.
-
Bleach (6 ounces algaecide):
- Added to the wash tank.
- Inhibits algae growth.
Developer Chemicals Breakdown
-
Reducers:
- Phenidone: builds gray tones, provides intermediate density, sensitive to light and temperature.
- Hydroquinone: builds blacks, provides upper scale density, sensitive to oxygen.
- Elon/Metol: added to hydroquinone in manual processing.
- PQ: used for automatic processing, 15x superadditivity than MQ.
- MQ: used for manual processing.
-
Buffer: maintains pH, source of alkali.
- Carbonate: Na or K carbonate.
- Boric Acid
-
Accelerator: speeds up the development process, allows the reducers to attack the AgBr crystals after swelling.
- Na or K hydroxide
-
Activator: facilitates swelling of gelatin.
- Alkalinizer: decreases and maintains level of pH, provides the necessary alkaline medium owing to the hydroxide.
-
Wetting Agent: stimulates uniform development by reducing surface tension.
-
Restrainer: prevents overdevelopment.
- K or Na bromide
- K or Na iodide
-
Regulator: Controls the activity of the reducers.
-
Anti-Foggant: Prevents chemical fog.
-
Starter Solution: added only to a fresh developer solution.
-
Benzothiosulfate Organic Restrainer: added only to PQ developer.
-
Preservative: Prevents rapid aerial oxidation.
- Na sulfite
- Cycon
-
Stabilizer: promotes equilibrium of chemicals.
-
Anti-oxidant: prevents rapid chemical oxidation, reacts with quinone, forming hydroquinone monosulfate.
-
Hardener/Tanning Agent: a weak hardener, prevents damage to the emulsion during transport.
- Glutaraldehyde
- Dialdehyde
-
Solvent: dilutes and concentrates the chemicals for proper strength.
- Distilled water
-
Anti-Sequestering Agent: an oily substance that prevents precipitation of aluminum and calcium, forms a sludge at the bottom of the tank.
- EDTA
- Chelates/Borate salts
- Calgon
-
Bleach 5% Fungicides: inhibits growth of fungi.
-
Anti-Frothant: Prevents bubble formation and aerial oxidation.
-
Replenisher: High in reducers, activator and preservative but w/o restrainer, can return the chemical activity to the original.
Stop Bath Chemicals
-
Acidifier: provides the necessary acid medium.
- Acetic acid
- Sulfuric acid
-
Neutralizer: neutralizes the developer and stops the development action.
- Acetic acid
Fixer Chemicals
-
Clearing Agent: dissolves and clears away unexposed silver halide crystals (pH 4.2 to 4.9)
- Ammonium thiosulfate
- Na thiosulfate
-
Fixing Agent: permanently fixes the image.
-
Hardener: shrinks and hardens the emulsion.
- K alum
- Chrome alum
- Al Chloride
-
Tanning Agent: increases temperature at which the gelatin softens.
- Chrome alum
-
Permanenting Agent: permanently fixes the image.
-
Preservative: prevents deterioration of chemicals and helps maintain chemical balance.
- Na or K sulfite
- Cycon
-
Anti-oxidant: prevents internal and external oxidation.
-
Stabilizer: maintains the equilibrium of the chemical in the solution.
-
Solvent:
- Distilled water
-
Sequestering Agent: an anti-sludging agent which delays precipitation of Al hydroxide (alkaline) by increasing pH.
- Borate salts
-
Hyponeutralizer: solution used between fixing stage and the final washing cycle to decrease the washing time of the film to prevent hyporetention.
- Acetic acid, silver nitrate and solvent
Other Processing Chemicals
- Hypokit: a chemical used to determine the presence of thiosulfate on processed films.
- Bleach 6 ounces algaecide: added to the wash tan.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz explores various chemicals used in photographic development, including reducers such as Phenidone and Hydroquinone, as well as buffers and accelerators. Learn about their properties, sensitivities, and roles in the developing process. Test your knowledge on the interactions and functions of these essential chemicals in photography.
