Industrial Radiography Film Processing

Industrial Radiography Film Processing

It has 4 parts
1) Developing 5-8 min Temp 68deg F (20deg C)
2) Stop Bath (Arresting development) 65-70dec F 30- 60 sec
3) Fixation – 65-70 deg F, 8-15min
4) Washing – 20-30min

Developing- developing solution has the ability to reduce the silver bromide crystals on the exposed part of films to metallic silver.
The time required to develop is 5 to 8 min at 20deg cent of solution (developer)
Longer developing time will produce chemical fog and this will decrease the film contrast.
Low temperatures can slow the action while the high temperatures can fog the film or soften the emulsion on the film so that it will wrinkle or wash off.


Stop Bath- (arresting development)
Once the development process has been completed it is necessary to stop the activity of the developer remaining in the film emulsion.
A stop bath can be made with a 25% acetic acid mixture with enough water to produce a gallon of solution.
Stop bath can also be produced by mixing 4 ½ OZ of glacial acetic acid per gallon of a bath.
Caution- when glacial acetic acid is used, great care should be taken because of the possibility of severe burns to the face and hands.
Acid should be added slowly to the water, never the water to the acid.
The proper stopping procedure is to remove the film from the developer, allow it to drain a few seconds (but not into the developer tank) and then immerse it in the stop bath for 30-60 seconds only.

Fixation- The developer does not change the unexposed silver bromide on the film, which means that the unexposed silver bromide remains on the emulsion and will darken upon exposure to the light.
To prevent this and the consequence ruining of the radiography, a fixer solution is used which removes the unexposed silver bromide without changing the silver deposits which compose the desired image.

The fixture solution also hardens the gelatin on the film so that it will stand to dry with warm air.
The fixing time for a film should be at least twice the time of developing (the time it takes to clear the undeveloped silver halide from the film (clearing time))

Fixing time is generally 8 to 15minutes.

The film should be agitated vigorously when placed in the fixture (sodium thiosulphate).

Washing- The next step in the film processing is thorough washing in running water so that the fixer will be diffused from the film.
The time required 20 to 30 minutes at 65-70deg F.

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