Processing of Latent Imaging Flashcards
Prepares the surface of the film for proper penetration
Wetting stage
Stages of processing (manual)
Wetting Development Rinsing Fixing Washing Drying
Penetrates the gelatin of the emulsion
Water
Converts the silver halide crystal to black metallic silver
Development stage
Chemical use in development stage
Development solution
Amount of blackening depends on:
Temperature
Time
Activity of developer chemicals
An up and down movement of tge film within the solution
Agitation
In manual processing , agitation should be limited to
5 seconds
Too much agitation will result to
Uneven development
Removes the excessive developer solution from the film’s surface before putting the film to the fixer solution
Rinsing stage
Used to neutralize the alkaline developer solution
Stop bath ( diluted acetic solution)
Rinsing in automatic is removed because of the presence of
Squeegee rollers
Removes the unexposed silver compounds and hardens gelatin
Fixing stage
Chemical use in fixing stage
Fixer solution
Activity of fixer solution is derermined by
pH level of solution
Silver concentration on fixer
Removes residual fixer from the film emulsion and remainder of soluble silver salts
Washing stage
Dries the film and completely hardens the gelatin
Drying stage
Container of the water
Master tank
Container of the developer and fixer solution
Insert tank
Quantitative method of measuring the degree of acidity or alkalinity of a solution
pH
The basis of the pH scale.
Pure water
Acid portion of the substance in a solution
H+ ion
Alkaline portion of the substance in a solution
OH
pH has a value of
0-14
_____ pH level is neutral
7
Developer for auto processing have a pH range of
9.6 - 10.6
Fixer for auto processing have a pH range of
4.2-4.9
Developer chemicals has 2 functions
Conversion
Selectivity
Convert crystal to black metallic silver
Conversion
Must differentiate between exposed silevr halide from unexposed silver halide
Selectivity
Converts exposed silver halide crystals to black metallic silver
Provides electrons to the crystal to change positive silver to black neutral silver
Developing agent / reducing agent
Solution which hydrogen concentration is practically unchanged by dilution
Buffer
Absorbing harmful by products of development action
Buffer
Loss of activity of developer
Exhaustion
Oxidation
Controls developer activity by ensuring correct pH
Gives alkaline in solution
Accelerator / activator
Improves selectivity of developer , ensuring low fog and high image contrast
Restrainer / anti-foggant
Reduce aerial oxidation to minimum
Preservative
Metods of reducing aerial oxidation
High preservative level
Floating lid
Closely fitting roller
Deep narrow tanks
Soften hard water supplies, preventing precipitation of the calcium and magnesium salts
Sequestering agent
Act as solvent for all chemicals
Solvent ( water)
Reduces emulsion swelling and softening ( automatic)
Hardening agent
Stimulate uniform development by reducing the surface tension bet ghe developing solution and film emulsion
Wetting agent ( detergent)
Reduce foaming mainly due to the presence of wetting agent
Anti - frothant ( anti- foaming)
Prevents the growth of fungi
Fungicide
Depresses the pH of the developer
Starter solution
Replaces the exhausted developer
Replenisher
Average replenishment is
40-60 ml for every 35 cm film
Factors affects to development
Time
Temperature
Concentration of chemical
2 fixer chemicals function
Conversion
Selectivity
Convert unexposed undeveloped silver halide crystals to soluble silver complexes
Conversion
Must no effect on either the metallic silver in the developed image w/c it us suspended
Selectivity
Converts unexposed, undeveloped silver bromide into water soluble silver complexes
Produces the transparent appearance of the film
Fixing agent /clearing agent
Agawan ng fixer at developer
Dichronic fog
Stop development by neutralizing tge alkali developer
Acid ( activator)
Maintain the pH of the fixing solution w/in fine tolerance
Buffer
Reduced to minimum the breakdown of fixing agent into sulfur particles
Preservative
Control the swelling and softening of the emulsion
Hardener
Average replenishment is
80-100 ml for every 35 cm film
Remove the remainder of the soluble silver complex salts that have not been removed by the water
Washing
Length of time a film will store w/i significant detoriation
Archival permanence
Responsible for yellow-brown strains
Salts
Uses two electrodes . Silver ions are attracted to tge cathode is neutralized
Electrolytic method
Types of manual processing
Time-temperature method
Sight development
Types of processing
Manual
Automatic
Day light system
Wash water passes through the steel wool fibers and silver ions exchanges with iron ions in the steel wool
Metal ion exchange
Sodium suphide is added to waste fixer
Precipitation