Film Processing (5)

Question 1

Five steps of manual film processing:

Answer 1

1. development
2. stopping the development/pre-wash
3. fixing
4. washing
5. drying

Question 2

Describe the Development process

Answer 2

Developing agent gives up electrons to convert silver halide grains to metallic silver.

• exposed grains develop rapidly, with enough time convert silver ions to silver metal.
• requires proper temp

Question 3

Chemicals that make up developer:

Answer 3

• Metol and hydroquinone (convert silver halide to black metallic silver)
• Sodium Carbonate (accelerate)
• Sodium sulphate (preservative, reduce oxidation)
• Potassium bromide or potassium iodide (ensure reduction of exposed grains only/restrainer)
• wetting, softening and anti-swelling agents (improve developer quality and lifespan)

Question 4

The rate of development is affected by the ____ of the solution.

Answer 4

temperature of the solution.

- as temperature rises, rate of development increases

Question 5

What is the most common developer temperature?

Answer 5

20°C or 68°F

Question 6

How are temperatures maintained in manual tanks?

Answer 6

immersion heaters/chill-chasers or heating elements (coils) around tank exteriors

Question 7

What is the average concentration of liquid developer?

Answer 7

10 litres per 40 litre tank of clean water.

Question 8

How can we monitor the activity of a developer?

Answer 8

test films, exposed under standard conditions. densities of exposures are measured and compared to densities of original exposures to determine any noticeable loss of gain in chemical activity.

Question 9

A loss in developer activity would result in a ____ in density values.

Answer 9

reduction in density values.

Increase density = increased activity, decreased density = decreased activity.

Question 10

What is the frequency of agitation in developer?

Answer 10

5-10 seconds for every minute f development.

Question 11

What is the Stop Bath’s purpose?

Answer 11

Deactivate the developer in the emulsion before the film goes into the fixer bath.

Question 12

What is the stop bath mixture made of?

Answer 12

25ml glacial acetic acid per litre of clean water

Question 13

What is the purpose of Fixing?

Answer 13

• Remove all undeveloped silver salt on the emulsion, leaving only the developed silver image.
• harden gelatin for subsequent drying

Question 14

Define “clearing time”

Answer 14

time interval between fixing the film and the disappearance of the original yellow “milkiness”.
- fixer is dissolving undeveloped halide crystals

Question 15

Total fixing time should be longer than the clearing time by ____ to ___ times.

Answer 15

2 to 3 times

Question 16

What temperature should the fixer be held at?

Answer 16

18-24°C

Question 17

Clearing time checks: once clearing times begin to exceed ___ to ___ minutes the original clearing time, it is time to ___ the fixer bath.

Answer 17

10 to 12 minutes of the original clearing time, it is time to change the fixer bath.

Question 18

Fixing time and agitation time:

Answer 18

no longer than 15 minutes

agitate every 1-2 minutes

Question 19

Describe Clearing time checks

Answer 19

performed regularly

• unexposed film in fixer solution and then observed .
• time required to remove silver is recorded and minimum fixing time is established (2-3X clearing time)

Question 20

Fixer solution mix:

Answer 20

10L solution per 40L water filled tank

Question 21

Chemicals that make up fixer:

Answer 21

• potassium alum (hardening agent)
• organic acid (neutralizer)
• sodium sulphate (preserve)
• salt buffer
• Hypo-clearing agent (solvent)

Question 22

Hourly rate of flow for a wash tank:

Answer 22

4-8x the volume of the wash tank

Question 23

What is the purpose of washing?

Answer 23

remove any remaining chemicals after the fixing

Question 24

Times and temperatures for washing

Answer 24

washed at minimum 20 minutes in non-circulated water (constant agitation required)

18-21° C not >25°C or <15°C

Question 25

What is the purpose of a wetting agent?

Answer 25

Reduce drying times and possibility of water marks.

done by reducing surface tension

Question 26

What is a wetting agent?

Answer 26

Photo-flow
also use jetdry or dish soap

100ml per 40L of water

Question 27

How long is film immersed in a wetting agent?

Answer 27

10 seconds prior to drying

Question 28

Describe the drying process:

Answer 28

• dry warm (28-48°C)
• do not prolong drying! can lead to brittleness, burns, melts
• circulated air
• built-in-fans, filters, heaters, desiccants

Question 29

Four steps of automatic film processing:

Answer 29

1. development
2. fixing
3. washing
4. drying

Question 30

Production time using an automatic film processor increase by:

Answer 30

10x

1.5 to 15 minutes

Question 31

Parts of an automatic processor:

Answer 31

• feed system/tray
• transport system
• auto replenishment
• temp control
• agitation system
• constant flow/wash system
• high-flow air system

Question 32

Advantages of automatic processing

Answer 32

• higher more consistent quality
• increase production
• no contact (reduced change of spillage)
• requires less space

Question 33

Disadvantages of automatic processing

Answer 33

• cost
• long warm up time
• maintenance
• back up incase of failure