Film Processing

Question 1

Basic steps

Answer 1

Development
Rinse/stop-bath
Fixing
Rinse
Drying

Question 2

What does developer solution do and name of process

Answer 2

Converts latent image to visible image

Conversion of exposed SHC to black metallic silver - reduction

Question 3

How long should film be immersed in developer and effect if left too long

Answer 3

~3-5mins

Unexposed SHC undergo reduction - uniform darkening of film

Question 4

What temp should developer be maintain at

What happens w/variation in temp

Answer 4

Constant 20c

Colder - underdevelopment
Hotter - overdevelopment

Question 5

Factors affecting developer exhaustion (3)

Answer 5

Depletion of active ingredients
Saturation w/bromide ions
Oxidation

Question 6

When should developer be completely replaced

Answer 6

Every 3 months or

When equal volume of replenished used

Question 7

Functions of stop-bath

How long is this stage

Answer 7

Stops development
Rinses developer from film
Prevents fixer contamination

10-30secs

Question 8

Functions of fixer

Fixer time

Answer 8

Clears unexposed SHC
Hardens gelatine coating (tanning)
- allows film to dry w/out damage

Twice development time (6-10mins)

Question 9

When should fixer be replaced

Answer 9

When clearing time exceeds 2-3mins

Question 10

Define clearing time

Answer 10

Time taken for removal of all unexposed SHC

Warm fixer clears faster

Question 11

If fixer over 21C May cause…

Answer 11

Staining

Question 12

Function of final rinse

Differences between manual and automatic

Answer 12

Removes fixing solution from film surface

Manual - 20-30mins w/periodic agitation
Automatic - constant flow

Question 13

What happens if film overdried

Answer 13

Emulsion layers crack over time

Question 14

Advantages of manual processing (2)

Answer 14

Cheaper

Produces excellent image quality if done well

Question 15

Disadvantages of manual processing (5)

Answer 15

Time consuming
H&S issues
Film storage req.
Diagnostic quality variable
Diagnostic delay

Question 16

Advantages of automatic processing over manual (4)

Answer 16

Less time & effort
Images viewed more quickly
Produces dry radiograph
Consistently high standard

Question 17

General properties of automatic processing (7)

Answer 17

Darkroom still req. to load/unload cassettes
Higher temp & more water than manual
Specially formulated chemicals to expedite process
Rollers transport film at constant speed
No stop-bath (squeegee rollers)
Dried by flow of warm air