1. Film Processing
Chapter 7

2. Film Processing
Proper film processing is vital to the production of a quality radiograph.
Processing can be done manually or automatically.

3. The Darkroom Three qualities of a good darkroom 1. Clean 2. Organized
3. Lightproof

5. Darkroom continued
Individual darkrooms may vary in design, but should all possess the same qualities.
Should be separate from the radiographic suite and should be used for only one purpose, processing exposed radiographs.

6. Darkrooms
Most of work in darkrooms is with minimal light (hence the word “Dark”).
Therefore layout should be such as to help reduce possibility of film damage.

7. Darkroom cleanliness
Should be clean as only room where intensifying screens and x-ray film is exposed to the air.
Should have proper climate control. Don’t want too humid.
Why?

8. Darkroom Organization
Should be organized so that all equipment can be located quickly and easily.
Should be two sides to the darkroom a dry side and a wet side.

9. Dry Side of Darkroom Where cassettes are unloaded and reloaded.
Should have countertop large enough to accommodate the largest cassette in an open position.
Countertop should be easy to clean.
Nothing “wet” should be brought to the dry side.

10. Dry side of Darkroom continued
Customary to store film under the dry table in a bin or cupboard.
How should film be stored?
Film hangers for each size film should be hung above the table on the dry side.

11. Film Hangers Available in two designs: Channel Hangers Clip Hangers
Tend to retain water and chemicals and need special cleaning and drying to prevent contaminations of the dry side.
Film must be removed from the channel hangers in order to be dried.
Clip Hangers
More fragile than channel hangers.
Clips can become weakened over time.
Lose ability to stretch the film.
Can puncture the corners of the film.
Can scratch other films.

12. Film Hangers

13. Wet Side of Darkroom Where actual chemical processing occurs.
Hand or manual processing consists of three tanks.
Developer
Water
Fixer

14. Manual processing tanks
Can be individually free standing.
Fixer and Developer can be placed in one large tank filled with thermostatically controlled water.
One of most important pieces of equipment is thermometer when using manual processing.
Processing chemicals must be certain temperature.

15. Wet side/ Drying area
Film drying area can consist of a film drying rack or a drying cabinet.
Drying rack should be dust free.
Drying cabinet is a heated forced-air unit that hastens the drying process.
Viewing screen is recommended on wet side of darkroom.

16. Darkroom Lightproofing
Light leaks can cause film fog.

17. Light leaks May be hard to perceive. Common sources of light leaks.
Entrance to dark room
Ceiling
From adjacent rooms

18. Lightproofing continued
Entrance should have double door or revolving door preferred but not always practical.
Make sure that door fits tightly into its frame.
Use weather stripping if needed to ensure light proofing.
Make sure that door LOCKS!

19. Ceiling/walls/etc
Suspended ceiling may have light leaks from adjacent rooms.
Walls should be light color as gives more reflection from the safety light.

20. Darkroom Safelight
Appropriate lighting in darkroom is crucial to good film development.
“Safe” light means light will not affect the film.
Safelights use a small-wattage bulb and a special filter to eliminate the light from the blue and green spectrum.
Bulb should be 15 watts or less.

21. Safelights continued
Should be positioned so that darkroom work can be performed without fumbling.
Two types of safe-lighting
Direct
Diffused light that shines directly over a work area such as the dry or wet side of the darkroom.
Indirect
A filtered light directed toward the ceiling and reflected over the entire room.
Two types of lighting may be combined.

22. Safelights continued
Safelight should never be closer than 4 feet to work area.
If too close may cause some film fog.

24. Film-Processing Solutions
Film processing consists of five basic steps.
1. Developing
2. Rinsing or stop bath
3. Fixing
4. Washing
5. Drying

25. Chemicals May be purchased in a variety of ways (liquids or powders).
May be in concentrated form and need to be diluted or mixed.
Preparing chemicals correctly is important or resulting solution may adversely affect the radiographic product.

26. Chemicals continued
Chemicals should be kept at specified room temperature.
Variances may adversely affect the radiographic product.
Too low temps, some of the chemicals may become sluggish in action and produce an under-developed or under-fixed radiograph.
Too high temps, may be too hot for manual control.

27. Chemicals All chemicals should be kept at same temperature.
Variances in temperature between the chemicals can result in film reticulation.
Reticulation- a darkroom artifact produced by variable chemical temperatures that cause irregular expansion and contraction of the film emulsion, resulting in a mottled density appearance.

28. Reticulation

29. The Developer
Developer-a chemical solution that converts the latent image to a visible image.
Primary function is to convert the exposed silver halide crystals to black metallic silver.
Developing time is specified by chemical manufacturer. Be sure to know this in your practice.

30. The Developer Continued
Developer temperatures affects the developing time.
Time-temperature developing is preferred over visual inspection when using manual processing.
Developer consists of developing agents, accelerators, preservatives, restrainers, hardeners, and a solvent.

31. Developing Agents
Composed of chemical compounds such as hydroquinone or phenidone that can convert exposed grains of silver halide to black metallic silver. The developing agent has little or no effect on the unexposed silver halide crystals.

32. Accelerators
Chemicals that increase the activity of the developer. Substances such as potassium carbonate or sodium carbonate are used to increase the pH to an alkaline range of 9.8 to This increase in pH causes the emulsion to swell and soften, allowing the developing agent to work more effectively.

33. Preservatives
Prevent the rapid oxidation that can occur with alkaline developing agents. They also help maintain a stable development rate and prevent straining of the emulsion layer.

34. Restrainers
Limit the action of the developing agent to the exposed silver bromide crystals in the film.

35. Hardeners
Often added to developers in automatic processors. They harden the film during processing and prevent excessive swelling of the emulsion. If the gelatin emulsion were to swell extensively, it could be damaged by the rollers in the automatic processor.

36. Solvent
Consists of water to dissolve the chemicals.

37. The Rinse Bath
After film is in Developer, retains a substantial amount of developer in the gelatin.
If film went straight from developer to fixer, then alkaline developer would neutralize acid of the fixer.
Rinse bath serves to stop the developing process, rinse the developer from film, and prevent carryover contamination to the fixer.

38. The Fixer Serves two basic functions
1. Clears unexposed silver halide crystals from the film.
2. It hardens the gelatin coating so that it can be dried without damaging the film surface.
General guideline is that film should be fixed for twice the development time.

39. Fixer consists of Clearing or fixing agents Preservatives Hardeners
Dissolve and remove unexposed silver halide crystals from the film emulsion.
Preservatives
Prevent decomposition of the fixing agent.
Hardeners
Prevent excessive swelling of gelatinous emulsion during fixation procedure and softening during the wash procedure. Shorten drying time.

40. Fixers Composition Continued
Acidifiers
Compounds that accelerate action of other chemicals and neutralize any alkaline developer possibly carried over into the acidic fix solution.
Buffers
Chemical compounds added to the solution to maintain the desired pH. Help to stabilize the acidity against the addition of alkaline developer carryover. Without buffer, developer would neutralize fix solution. Can also prevent sludge formation in the fix bath.

41. Fixer Composition continued
Solvent
Consists of water.
Purpose is to dissolve other ingredients and assist in the fixing agent to diffuse into the emulsion layer of the film.
Carried silver halide away from film.

42. The Wash bath Wash portion is vital to a quality radiograph.
If film is not washed properly for a long enough period of time, the image will eventually discolor and fade.
Films should be washed in circulating water so both surfaces of film receive water continuously.
Manual processing wash time is recommended mins.

43. Wetting Agent
Water spots and streaks is a problem with drip drying films in manual processing.
A wetting agent bath can hasten drying process. Called Surface-tension reducing agent.

44. Water spots/bubbles

45. Solution Replenisher
In manual processing, chemical depletion is a natural result of chemical carryover into adjacent tanks.
Up to 60 mL of developer can be carried on a film into rinse bath.
Developer and fixer need frequent replenishment.
Replenishment is available in powder and liquid concentration form.
Generally will have higher concentration than original solution in order to maintain chemical potency.

46. Solution Replacement
Used/old chemicals are primary cause of poor-quality radiographs.
Check chemicals every time PRIOR to development of film.
Developer may turn from green to brown.
In general, chemicals should be changed every 4-6 weeks.
Depends on frequency of use.

47. Biologic Growth In manual processing may have bacterial growth.
Need to be controlled.
When changing chemicals, clean tanks as well.
Wash tank of automatic processor should be drained at end of day to prevent growth.

48. Film-processing Techniques
Two types of processing:
Manual
May take up to an hour to develop
Automatic
Generally can be processed in 90 seconds
Both types of processing can produce a quality radiograph, it is a matter of preference.

49. Manual-Processing Procedure
Step 1.
Preparation
Make sure that chemicals should be at proper temperature and should be stirred.
Step 2.
Unloading the cassette
Take care when unloading cassette. Careful with fingernails! (Why?)
X-ray film should be handled by corners and edges only.

50. Manual Processing Procedure cont.
Step 3.
Loading the film on a hanger
Clip hanger – load the bottom first
Stretch to “bounce a coin on it”
Will prevent the film from touching other films or walls while developing
Channel hanger
Held in one hand while sliding the film into the channels with the other
All sides and corners should be checked for proper placement
Once in place, the top can be closed

51. Manual Processing Continued
Step 4.
Developing the film
Immersed in developing tank and agitated two or three times.
Step 5.
Rinsing the film
Remove film from developer.
Immerse in rinse bath and agitated for 30 seconds.

52. Over-rinsed film

53. Manual Processing Cont.
Step 6.
Fixing the Film
Removed from rinse tank and immersed in the fix tank.
Step 7.
Washing the Film
Removed from Fixer and washed mins.

54. Left in Fixer

55. Under washed film

56. Manual Processing cont.
Step 8.
Optional Final Rinse
Application of a wetting agent.
Step 9.
Drying the film
Film is dried in dust-free environment to prevent artifacts.
Make sure well seperated.

57. No Final Wash Applied

58. Automatic Processing Advantages over the manual method.
1. highly standardized procedure with consistent quality.
2. can produce a dry radiograph in a short amount of time.
3. reduces labor time of employees.
4. smaller darkroom space required.

59. Automatic Processors Roughly same procedure as manual processing.
Operate at higher temps and have specifically formulated chemicals to speed development.
Film is transported through processor by a series of rollers.

60. Automatic Processor continued
Chemicals still need to be checked and processor warmed up.
Make sure that films are fed one at a time to prevent sticking together.
Will be signaled by the processor when can feed next film.

62. Stuck in processor

63. Films stuck together

64. Folded Film

65. Processing Chemicals
In automatic processing, chemicals are replenished as they are used.
Temperature is also constantly monitored.
Chemicals are re-circulated.

66. Processor Maintenance
Can be serviced by a professional
Quick tech checks:
Check solution levels
Check replenishment rate
Check temperature
Check roller operation
Rinse and wipe rollers racks
Clean tanks

67. Silver Recovery Recycle to obtain silver from development process.
3 methods of silver recovery
1. Metallic replacement
2. Electrolyte recovery
3. Chemical precipitation

68. Film Identification
Proper Labeling and identification of x-ray films is VITAL!!!!!
All labeling systems should include.
1. name and address of hospital practice or veterinarian.
2. date the radiograph was take.
3. patient identification including name of the owner and patient name, age, sex, and breed.

69. Lead Blockers
Identification can be done via lead lettering, lead impregnated tape, or photoimprinting labels.

70. Other markers
Right (R) and Left (L) markers are essential to identify size and position of image on radiograph.
May need to label front and rear as well especially in large animals.
If label not a part of film itself,then can add later with marker, or scratching into film while still wet.

71. See markers

72. Film Filing
Organized film filing system is needed in veterinary practice.
Must be placed in suitable holder and filed appropriately.
Should be labeled, numbered if necessary and filed correctly for easy future reference.
X-ray logs also help with film identification.