Physics Unit 3

Question 1

Film Processing

Answer 1

Latent image has too few silver atoms to produce a visible image.
Processing multiplies the number of silver atoms at the sensitivity center making the image visible.

Question 2

Automatic Processing

Answer 2

first automatic processor was introduced by Pako in 1943
Used special film hangers and dip tanks
Could process 120 films p/hr.
took approximately 40 minutes to process onefilm

Question 3

1956 Kodak

Answer 3

developed the first roller transport system which advanced film processing significantly

Question 4

1965 Kodak

Answer 4

introduced the first 90 second processor
possible because of advancements in chemistry and polyester film base
still widely used

Question 5

1987 Konica

Answer 5

introduced a 45 second processor but this unit requires special chemicals and films

Question 6

Manual Processing Sequence

Answer 6

Wetting- swells emulsion
Developing- converts latent image to visible image
Rinsing/stop bath- stops developer action
Fixing- preserves image
Washing- rinses chemicals
Drying- dries, that’s pretty much it.

Question 7

Automatic Processing

Answer 7

Developer
Fixer
Wash
Dry

Question 8

Processing Chemicals

Wetting

Answer 8

Wetting- causes emulsion to swell so processing chemicals can penetrate the emulsion
uses water
Water is the UNIVERSAL SOLVENT which all the chemicals used in processing can be dissolved into.

Question 9

Processing Chemicals

Developer

Answer 9

Changes silver ions of exposed crystals into metallic silver
Provides electrons to sensitivity center of crystal to change silver ions into metallic silver
Silver ion is reduced to metallic silver
Reduction uses electrons, oxidation provides electrons
EUR-OPE:
Electrons Used during Reduction
Oxidation Provides Electrons
Silver Halide Crystals will not allow electrons in unless they have been exposed to radiation
Unexposed crystals have a negative exterior and a positive interior electron will be repelled
Silver halide crystals which have been exposed possess a “GATE” which allows electrons to enter and convert the silver ions intpo metallic silver
More ions at sensitivity speck the larger the gate.

Question 10

4 Silver Atoms

Answer 10

there must be at least 4 silver atoms at the sensitivity center in order for the crystal to have an open gate.

Question 11

Rinsing/ Stop Bath

Answer 11

Stops developer action by neutralizing the pH of the emulsion
In Fixer in automatic processor

Question 12

Fixer

Answer 12

AKA hypo, thiosulfate, thio, clearing agent
Removes unexposed and underdeveloped silver halide crystals from the emulsion
Hypo retention is when some of the fixer remains in the emulsion and oxidizes over time causing the film to turn yellow

Question 13

Washing

Answer 13

Removes as much of the developer and fixer as possible

Water, the universal solvent is used

Question 14

Automatic Processing

Answer 14

Transport System
Temperature Control System
Circulation System
Replenishment System
Dryer System

Question 15

Transport System

Answer 15

Film is inserted into the film tray and picked up by the entrance rollers.
Microswitch senses film and controls replenishment rate of chemicals
Shorter side of film should be up against the edge of the side rail so less processing chemical is used
Alternate sides of the film tray to prevent wear on rollers
Film is transported through processor by rollers through developer tank, fixer tank, water tank and dryer system.
1 inch transport rollers move film, master rollers, planetary rollers, and guide shoes are responsible for turning the film around

Question 16

Temperature Control System

Answer 16

Regulates temperature of chemical tanks
Developer temperature is critical
Must be maintained at 95 degrees F
High temp will cause over development, low temp will cause under development
Water needs to be maintained at 90 degrees F

Question 17

Circulation System

Answer 17

Agitation continually mixes the chemicals, maintains temperature, and aids exposure to chemicals.
Continuously pumps developer and fixer
Developer is filtered to remove trapped bits of emulsion, unnecessary in fixer
Water is an open system, fresh tap water is pumped in at a rate of 3 gal/min

Question 18

Replenishment System

Answer 18

Some of the chemical is absorbed into the emulsion of the film, some is carried over into the next tank.
Replenishment system replaces used chemicals
Microswitch controls how much replacement chemical is needed
Approx 60-70 ml of developer and 100-110 ml of fixer is used for every 14 inches of film developed
Water is continuously replenished

Question 19

Dryer System

Answer 19

Dries film uses blower fan, warm air on both sides
Hot, moist chemical air is exhausted externally
Moist film is often caused by depleted hardener in the fixer.
Wet film can pick up dust, causing artifacts.