5: Film Handling Flashcards
The activity of the developer solution is maintained stable by doing what?
Adding the replenisher
How can water spots on films be minimized?
Immersing wet film for one or two minutes in a wetting agent solution.
The film flaw that results from incorrect or unsuitable darkroom safe-lighting is what?
Overall grey fogging
What does the developer convert?
Silver ions into silver metal
How must walls be painted in a darkroom?
With lightly coloured semi gloss paint
What is of utmost important in a mobile darkroom?
Cleanliness and organization
What’s the industry rule of thumb for how long film should be in the fixer?
2x as long as developer
Eventual browning of film can be caused by which process of development?
Improper fixer
What is the correct order of manual development? (6)
- Developer
- Stop bath
- Fixer
- Wash/rinse
- Wetting agent
- Dryer
Temperature should not decrease below ___ in the developer.
60 degrees F
What colour is fresh stop bath solution?
Yellow, but clear under safe light
What are the 2 purposes for the fixer bath?
- Dissolves/removes silver bromide from undeveloped portions of film
- Hardens emulsion gelatin
With proper care, how long can fixer solution last?
Up to 3 months
Washing should take how long as fixer?
2x time it took to “fix”
What may be used to speed up film washing?
Hypo clearing agent
What artifact can occur due to rollers in an automatic processing until?
PI Lines, 3.14x diameter of roller - chemical deposits
In the Time-Distance Relation, mA is directly proportional to what?
Square of focal film distance
If you double your distance, time will increase by what?
Factor of 4
Therefor if you increase by 1, time will increase by 2…
SFD rule of thumb:
Not less than 8x the thickness of test object
What may be required for mobile darkrooms to prevent a build up of residues or increased processing times?
Water conditions and hardening agents
Prior to “fog tests,” how long should lights be warmed up for?
10 minutes
Properly processed radiographs should have an archival quality life of how long?
20-50 years
Why is proper temperature control needed in the developer?
To convert exposed grains to pure silver while keeping unexposed grains as silver halide crystals
What type of solution if the developer?
Alkaline
What are often around the outside of tanks to maintain temp in manual systems?
Immersion heaters (chill-chasers) or heating elements (coils)
What does a replenished do to the developer?
Maintains activity stability of developer solution
When testing the developer with test film, what is a good indication that it’s time to dispose?
When test exposures have a lesser density compared to the original/standard films
What is the purpose of agitating the developer?
To secure uniform development over whole film area
5-10 seconds for every minute of development
What is the recommended spacing between each rack processing?
25 mm
What is the purpose of the stop bath?
To deactivate developer remaining in emulsion (acidic stop bath)
Per litre of water, how much glacial acetic acid (household vinegar is a common alternative) should be added to stop bath?
25 mL (generally)
What are the 2 purposes of the fixer?
- Remove all undeveloped silver salt from emulsion
2. Harden film gelatin so film will withstand subsequent drying w/ warm air
What is the “clearing time”?
The interval between fixer solution and disappearance of “milkiness”
(Fixing/dissolving undissolved crystals)
Total fixing time should be how much longer than clearing time?
Approximately 2-3x
If clearing time starts to exceed _____ min of original, it’s likely time to change bath.
10-12 min
In general, washing of films should be at a minimum of ________.
20 min
Temperature of washing should be between how much?
18-21 degrees Celsius
NOT below 15, or above 25
What is a wetting agent used for?
Decrease drying time and possibility of water marks
What is a common industrial and house hold option for a wetting agent?
Industrial: photo flow
Household: jet dry and regular dish soap
For mobile darkrooms, approx ______ of wetting agent per 40 litres of water.
100 mL
What is the UTMOST importance regarding the drying stage?
Films should only stay there until dry
Circulating air in the dryer should be between what temps?
28-48 degrees Celsius
What step is eliminated in the automatic processing step?
Stop bath
What is dichroic fog?
A chemical fog on surface of film causing discolouration when viewed by reflected light.
(Usually a result of exhausted solutions)
Puckered/net-like linkages are caused by what?
Reticulation
Why do blisters occur?
A reaction between the alkaline developed and acid fixing bath
What are the 3 main steps to processing radiographic film?
- Developing
- Fixing
- Washing
Film artifacts, such as crimps and static marks, can occur at any time but are almost always a result of what?
Poor handling techniques
The time it takes for the unexposed silver halide grains to be removed from the film in the fix bath is referred to as the what?
Clearing time
In general, the purpose of agitating the film during development is to what?
Renew the developer on the film surface
Film and film processing chemical manufacturers recommend a standard time and temperature for manually processing radiographic film. What are they?
5 min @ 68 degrees F
Water spots on films can be minimized by what?
Immersing wet film for 1-2 minutes in a wetting agent solution.
In order to achieve uniformity of development over the area of X-ray film during manual processing:
The film should be agitated while in the developer
A significance difference between manual and automatic film processing is that..
No stop bath is used after development in automatic system
The film flaw that results from incorrect or unsuitable darkroom safe lighting is what?
Overall grey fogging
