Film Processing Essentials: Darkroom Functions and Operation

1. Darkroom and Film Processing Rad Tech A – Week 10Fall 2007

2. Darkroom

3. Darkrooms – Still Necessary? • Darkrooms are necessary for manually fed processors and daylight processors. -Loading automatic film processor magazines. • Necessary for conducting certain quality control tests (daily sensitometric strip).

4. Darkroom

5. Darkrooms 4 Basic Functions • Number 1 Function • Storage • Unexposed film

6. Film Bin

9. DARKROOM FUNCTION # 2 Purpose of Film Processing • Change silver halide crystals from film emulsion (after exposure to x-ray or light photons) to black metallic silver. • Latent image (invisible until processed) is developed into a Manifest image. • Improper or careless processing can cause poor diagnostic quality.

10. Manual Feed Processor

11. Hand Processing in the Early years • Strong smell of chemicals • Messy • Time consuming

12. 1956 – first roller transport6 minute processing time

13. Processing Time 3 minutes 90 seconds

14. Processing FilmTable top Processors Can process as fast as 60 seconds TABLE TOP PROCESSOR

15. PROCSSING CHEMICALS • Solutions are PRE- MIXED • Outside Company usually provides service- • Weekly or monthly • Solutions should be replenished as necessary & changed regularly • Solutions must be monitored (Daily QC strip).

16. Replenishment tanks

17. TABLE TOP FILM DUPLICATORto MAKE COPIES OF FILMS

18. WILL THIS WORK ????

19. Daylight Processor

20. Function # 3: Handling of Film

21. UNLOAD EXPOSED FILM

22. Function # 4: Film Identification • Pt name • Exam date & time • Pt x-ray number • Pt Birthday/DOB • Rt or Lt marker • Optional • Exam type • Dr. Name

23. FILM ID PRINTER Name of patient place on top Cassette is “flashed” with name – can be done before or after image is taken Should be done BEFORE PROCESSING FILM

24. TRANSPORTATION SYSTEM DEVELOPER FIXER WASHER DRYER REPLENISHMENT SYSTEM AUTOMATIC PROCESSING

25. Automatic Processor

26. Processor Chemistry Overview • Developer– converts latent image into manifest image • Fixer– clear the film of unexposed, undeveloped silver bromide crystals, promotes archival quality • Wash – rid the film of residual chemicals

27. Developer Solution(6 Ingredients) • Reducing Agent: reduce exposed silver halide to black metallic silver -Hydroquinone (Blacks) -Phenidone (Grays) 2. Activator:softens gelatin, maintains alkaline pH (increase pH) -Sodium Carbonate

28. Developer Solution 3. Hardener: prevents damage to the film from over swelling of gelatin in automatic processors. -Gluteraldehyde 4. Preservative: Antioxidant that prevents oxidation of developer -Sodium Sulfite

29. Developer Solution 5. Restrainer:prevents chemical fog in new developer -Potassium Bromide 6. Solvent:dissolves & ionizes the developer chemicals -Water

30. Fixer Solution(5 Ingredients) • Clearing Agent:dissolves undeveloped silver halide -Ammonium Thiosulfate 2. Tanning Agent:shrinks, hardens, preserves emulsion -Aluminum Salt

31. Fixer Solution 3. Activator:neutralizes developer, maintains acidic pH (decrease pH) -Acetic Acid 4. Preservative:prevents oxidation, prolongs solution life -Sodium Sulfite 5. Solvent:dissolves other ingredients -Water

32. Wash • Rid the film of residual chemicals for developer and fixer • Residual chemicals on the film will discolor radiograph over time. • Cold water processors are less efficient in removing chemicals – Warm water processors much better. • Agitation during wash process is essential

33. Fixer Retention(Not Washed Off)

34. Transport System Components • Feed Tray • Rollers (Different Assemblies): 1. Entrance 2. Deep Racks 3. Turnaround 4. Crossover 5. Squeegee 6. Dryer • Receiving Bin

35. Transport System (Rollers) Entrance Crossover Feed Tray Squeegee DeepRacks Dryer Turnaround

36. Processor (Top View)

37. Replenishment System • Main function: Keep solution tanks full and assure proper solution concentration. • As film is introduced into processor, sensor initiates solution replenishment • Right & wrong way to feed in film -Feed in along short edge

38. Transport System in Automatic Processors • Conveys the film through different solutions (sections) by a series of rollers driven by gears, chains & sprockets. • Done at a prescribed speed – determines length of time the film is in each solution

39. Temperature Regulation • Main function: To control the temperature of each section of the processor. • Developer – most important solution to regulate • Usually between 92 degrees and 95 degrees • Thermostatically controlled

40. Recirculation System • Provides agitation necessary for uniform solution concentration

41. Wash & Dryer Systems • Wash: Provide thorough removal of chemical solutions from the film. -Archival film quality • Dryer: Removes water from film by blowing warm, dry air -Between 120 degrees & 130 degrees F.

42. Silver Recovery • About ½ of the film’s silver remains in the emulsion after exposure & processing. • Other ½ (unexposed silver) is removed from the film during fixing process. • Silver is toxic to public water supply – must have proper disposal.

43. What is in the Darkroom?

44. Loading Bench Film Bin Film I.D. Printer Safelights Pass Box Light-tight Room Ample ventilation Warning Light outside room Lockable Door Wall Shielding if adjacent to x-ray room Walls painted with light color to reflect safelight Darkroom Contents

46. Darkroom Equipment

47. Darkroom Equipment

48. Safe Light • 15 Watts • Red filter • Must be 3-6 feet from counter top or feed tray of processor • Used to be amber or orange filter

49. Darkroom Summary

50. Summary & Questions