Midterm Lesson 1 Flashcards
The most important consideration in selecting screen film is ———?
• Spectral Matching
For the screen to work at maximum efficiency, the ——— of the film must match to the light from the screen
the light absorption characteristic
screen that emits blue and blue-violet light
a) Calcium Tungstate Screen
screen that emits ultraviolet, blue, green, and red light
b) Rare-Earth Elements
What are the three RARE EARTH ELEMENTS
Ytrrium, Gadolinium, Lanthanum
All silver halide film responds to
violet and blue
All silver halide film does not respond to ——— unless they are spectrally sensitized
GREEN, YELLOW, AND RED
3 Types of Film according to its Sensitivity
- Orthochromatic Film
- Monochromatic Film
- Panchromatic Film
sensitive to the entire visible light spectrum
Panchromatic Film
blue and green sensitive film
Monochromatic Film
green sensitive film
Orthochromatic Film
Filter used for blue sensitive film and its wavelength
Amber Filter (550 nm wavelength)
Filter used for green and blue sensitive film and its wavelength
Red Filter (600 nm wavelength)
Ideal film humidity
50%
Film humidity greater than 60% results in?
Increased fog
Film humidity lesser than 40% results in?
Static Artifacts on the Film
- serves as a water jacket to hold insert tanks
- usually, large enough to provide space between insert tanks for rinsing and washing of films
Master Tanks
- Removable containers for the individual processing solutions (developer nd dixer)
- Are spaced in master tanks
Insert Tanks
- prevents stagnant water
Overflow Valve
- The term applied to chemical reactions that transform the latent image into a manifest image
Film Processing
Film Processing Steps
Development
Rinsing
Fixing
Washing
Drying
During ———, it penetrates the gelatin of the emulsion, causing it to swell.
wetting
In automatic processor, the wetting agent is in the ———.
developer
• The primary function of ——— is to convert the latent image into a visible image.
• A very short and critical stage where the latent image is converted to manifest image
development
Principal action of the ——— is to change the silver ions of exposed crystals into metallic silver.
developer
The step when development is complete and then the film must be treated so that the image will not fade.
The image is said to be ——— on the film, and this produces film of archival quality.
Fixing, Fixed
This stage in processing is to remove any residual chemicals remaining in the emulsion, particularly hypo that clings to the surface of the film.
Washing
Wash water should be maintained at approximately ——— below the developer temperature.
3°C (5°F)
serves to stabilize developer temperature
Wash bath
Inadequate washing leads to ——— and the production of an image that will fade will turn ——— over time and be of ———
Inadequate washing leads to excessive hypo-retention and the production of an image that will fade will turn brown over time and be of generally poor archival quality
Final step of film processing
Drying
Time of Drying for Manual and Automatic Processing
• Manual Processing – takes longer than 1 hour to be completed.
• Automatic Processing - the dry-to-drop time is 90 seconds
refers to the permanence of the radiograph
Archival Quality
Developer Chemical that acts as a Reducing agent; produces shades of gray rapidly
Phenidone & Metol
Developer Chemical that acts as Reducing agent; produces shades of black slowly
Hydroquinone
Developer Chemical that Helps well gelatin; produces alkalinity; controls pH
Sodium Carbonate
Developer Chemical that Helps well gelatin; produces alkalinity; controls pH
Sodium Carbonate
Developer chemical that acts as a Antifog agent; protects unexposed crystals from chemical “attack”
Potassium Bromide
Developer chemical that Controls oxidation and maintains balance among developer components
Sodium Sulfite
Developer chemical that Controls emulsion swelling and enhances archival quality
Glutaraldehyde
Developer chemical that Removes metallic impurities; stabilizes developing agent
Chelates
Developer chemical that Dissolves chemicals for use
Water
The Developer contains alkali components or buffering agents, what are they?
Sodium Carbonate
Sodium Hydroxide
aka lye, strongest alkali
Sodium Hydroxide
Purpose is to enhance the action of the developing agent and controlling the concentration of hydrogen ions (pH)
alkali components or buffering agents
neutralize positive ion
Reduction
opposite of reduction; reaction that produces electron
Oxidation
reduction and oxidation work simultaneously
Redox reaction
EUR / OPE
Elextrons Used Reduction
Oxidation Produces Electrons
Fixer component and chemical that: Neutralizes developer to stop its action
Activator - Acetic Acid
Fixer component and chemical that: Removes undeveloped silver bromine from the emulsion
Fixing Agent - Ammonium Thiosulfate
Fixer component and chemical that: Stiffens and shrinks emulsion
Hardener - Potassium Alum
Fixer component and chemical that: Maintains chemical balance
Preservative - Sodium Sulfite
Fixer component and chemical that: Maintains proper pH
Buffering Agent - Acetate
Fixer component and chemical that: Removes aluminum ions
Sequestering Agent - Boric Acids/Salts
Fixer component and chemical that: Disolves other components
Solvent - Water
term used to describe the undesirable retention of the fixer in the emulsion
Hyporentention
——— slowly oxidizes and causes the image to discolor to brown over a long time.
Excess hypo
Principal Components Of Automatic Processor
A. Transport System
B. Temperature System
C. Circulation System
D.Replenishment System
E. Dryer System
Transports film throughout various stages at precise intervals
Transport System
Three Systems of Transport System
i. Feed Tray
ii. Entrance Rollers
iii. Microswitch
where film to be processed in inserted into the processor
Feed Tray
grips the film to begin its trip through the processor
Entrance Rollers
is engaged to control the replenishment rate of the processing chemicals.
Microswitch
Three Principal Transport Subsystems
- Rollers
- Transport Racks
- Drive Motor
- With a 1 diameter of 1 inch, convey the film along its path.
- They are positioned opposite one another in pairs or are often offset from one another
Transport Rollers
- Smaller rack assembly that is composed of rollers and guide shoes.
- Guide to transport the film to the next assembly
Crossover racks
diameter of 3 inches, is used in when the film makes a turn in the processor.
Master Rollers
1 inch in diameter (25mm) that supports the master rollers
Planetary Rollers
curved metal lip, smoothly guides the film around the bend
Guide Shoe
provides the fractional horsepower
Drive Motor
- Developer temperature is most critical and it is usually maintained at ———
35°C or 95°F
Wash water is maintained at ——— lower.
3°C or 5°F
monitors the temperature
Thermocouple/thermistor
Agitation is necessary to …? (3)
✓ continually mix the processing chemicals,
✓ maintain a constant temperature throughout the processing tank, and:
✓ aid exposure of the emulsion to the chemicals.
In automatic processing, —— continuously pumps the developer and the fixer, thus maintaining a constant agitation within each tank
the circulation system
meters the proper quantities of chemicals into each tank to maintain volume and chemical activity
Replenishment System
Replenishment Rate of Developer and Fixer
• Developer – 60-70 ml
• Fixer – 100-110 ml (for every 35 cm or 14 inch of film)
extracts all residual moisture from the processed radiograph, so it drops into the receiving bin dry
The dryer system
The Dryer System consists of
a. blower
b. ventilation ducts
c. drying tubes, and;
d. exhaust system.
