2. Radiographic darkroom
Dark room is a place where the necessary handling and processing of films can be carried out safely and efficiently, without the hazard of producing ‘film fog’ by accidental exposure to light or x-rays

3. Complete blackout is unnecessary.
Safe illumination is required to facilitate darkroom procedures.
It must exclude all outside light and provide safe artificial light.

4. Darkroom construction
Darkroom illumination
Darkroom equipments and its arrangement
Health and safety in processing area

5. LOCATION Centrally located
Serviced by hatches from the adjacent imaging room
Away from damp or hot areas
Accessible in terms of power and water supply
Adjoining viewing room
Completely light proof – no windows

6. CENTRALLY LOCATED DARK ROOM

7. PASS BOX Two light tight and x-ray proof doors
Both cannot be opened at the same time.

8. SIZE Minimum floor area of 10 sq m Ceiling height of 2.7 – 3.3 m
Size may be increased depending upon the department needs

9. RADIATION PROTECTION
Walls adjacent to the radiographic rooms should be shielded with correct thickness of the lead – 2 mm lead or its equivalent
25mm high quality barium plaster
225 mm thick single brick wall
150 mm thick concrete

10. X-ray apparatus in the adjacent room should be properly placed – primary beam never be directed at the darkroom wall.
Radioactive materials should be stored as remotely as possible from the darkroom.

11. FLOOR Non-porous Non-slippery Chemical resistant Stain proof
Durable & easy to maintain
Light coloured (low-light working conditions)

12. Asphalt tiles
Porcelain tiles
Clay tiles
Plastic tiles may be used in the dry dark-rooms
Walls adjacent to the sinks and wet processing equipment should be protected to 1.3 m height

13. WALLS & CEILING
Light in colour to reflect as much light as possible onto the working surface
A glossy cream or white paint(to obtain as much as reflected light as possible).
Good quality paint, non-flaking
Easy to wipe or clean
Covered with chemical resistant materials
Special paints, varnish, ceramic or plastic wall

14. Ceiling should be at least 2.7 m high
Non-flaking emulsion paint
Any water pipes, electric cables or AC ducts to be enclosed above a false ceiling

15. VENTILATION AND HEATING
Satisfactory working conditions for the staff
Adequate processing conditions
Efficient automatic processor performance
Adequate removal of stale humid air and supply of fresh air
Intake and extract fans can be used

16. Relative humidity is maintained at around 40-60 %
Room temperature maintained between degree celsius
A minimum of air changes per hour
Minimum of 1000 cu.ft. airspace/person

17. All of these conditions can be achieved by using a good air-conditioning system
Exhaust fan if used are provided with a cowl on the outside – light proof and protect against wind pressures

18. TYPE OF ENTRANCE Single door system Double door system
Maze and Labyrinth
Revolving door system

19. SINGLE DOOR ENTRANCE Latch or lock from inside
Capable of releasing the lock from outside in case of emergency
Emergency exit
Ideally no one should work alone in a dark room

20. DOUBLE DOOR ENTRANCE

21. Double door plan with interlocked doors

22. MAZE TYPE ENTRANCE M A Z E

23. LABYRINTH TYPE ENTRANCE
Light is reflected at least 3 times. Intensity is reduced to a harmless level.
Black paint for the interior of the passages
Matt black paint
Vertical height- 2m
Length – not less than 3 m
Width – not more than 700mm
Safelamps fitted along the passageway

24. Advantages of labyrinth:
Easy and instant access to dark room
No hazard to single-handed operator
Allows for fresh air to come in

25. REVOLVING DOOR ENTRANCE
3 feet in diameter.
Extends about 15” into each adjoining room.
Lightproof access to the room.

26. DARK ROOM ILLUMINATION
White lighting
Safelighting

27. WHITE LIGHTING For inspection & maintenance of cassettes & screens
Cleaning of work surfaces
Servicing of equipment, changing solutions

28. Sited close to the ceiling ; Preferably centrally placed
Moderate in intensity (60w tungsten, 30w fluorescent )

29. SAFE LIGHTING
A source of light which will not fog the films and still provide adequate illumination under processing conditions.
Consists of a lamp fixture in which a pearl bulb of 25 W is used with a colored filter placed in front of the bulb
However no safe light is completely safe – depends on wavelength /color , intensity of light and duration of exposure.

30. How does a safelight work ?

31. Color of the filter depends upon the sensitivity of the x-ray film
Eg: Kodak GS-1filter with green sensitive Ortho-G film
Usually brown or olive-green lighting is used – represents region of the spectrum for which we have greatest visual sensitivity at low levels of illumination

32. Two types :
Direct safe lighting
Indirect safe lighting

33. SAFE-LIGHT LAMP
Direct safe lighting : light from safe lamp directly falls onto the work surface
Minimum distance of 1.2 m (4 feet) from the working surface
Best for loading & unloading areas

34. DIRECT SAFE LIGHT

35. Indirect safe lighting : directs the light towards the ceiling which reflects light back into the room
Is intended to provide general illumination of the dark room
Suspended atleast 2.1 m above floor level
One for every 6.5 m2 of floor space

36. Safe lamp for both direct & indirect illumination
Filters on both upper and
lower surface

37. Combination Safelight
Combination Safelight is a unique two-compartment unit features a safelight at the bottom and a normal room light at the top

38. SAFE LIGHT FILTERS
Sheet of gelatin dyed to the appropriate colour and sandwiched between two sheets of glass for protection
Used in conjunction with a 25 W lamp
Extremes of heat and moisture deteriorates the filter gelatin
Should be cleaned periodically

39. TESTING FOR THE SAFETY OF SAFELIGHT
WHEN IS TESTING REQUIRED ?
Darkroom is a new one
Safelights have been changed
New method or technique
If a particular lamp is suspect as causing fogging

40. Film is subjected to very small exposure, just enough to cause graying
In the darkroom, one half is covered with black paper and other half exposed in the safelight
Film is processed
If uncovered portion is darker, darkroom lighting is not safe.

41. DARK ROOM EQUIPMENTS
AND
LAYOUT

42. Darkroom equipment With automatic processing
With manual processing unit
Manual processing unit
Loading bench
For film storage – hopper/drawers/ cupboards.
Cassette racks
Cassette hatches
Darkroom sink
Hangers for suspending film
Processing chemicals + storage place.
Drier
Automatic processor
Loading bench
For film storage – hopper/drawers/ cupboards.
Cassette racks
Cassette hatches

43. PROCESSING APPARATUS
1. MANUAL PROCESSING
2.AUTOMATIC PROCESSING

44. AUTOMATIC PROCESSOR
Through the wall position for an automatic processor

45. MANUAL PROCESSING UNIT
MATERIAL – PVC /Stainless steel
ARRAY OF TANKS FOR MANUAL PROCESSING

46. The loading bench:
Long enough to allow 3–4 cassettes to be placed side by side.
Min length 2.5m per operator
600 mm min width
Min 900 mm high
Top – hard wood – teak covered with linoleum ( easy to clean, hard wearing, anti-static)
Formica is not recommended.

47. Film hopper: Stores the unexposed films intended for immediate use
Under the loading bench
Cone shaped drawer hinged at the lower edge
Inside is painted black
Prominent WARNING should be written on outside that it should not be opened in white light
Instead drawers and cupboards can also be used to store unused films

48. FILM HOPPER FOR THE STORAGE OF UNEXPOSED FILMS

49. Cassette hatch : Two light tight and x-ray proof doors
Should open on the loading bench.
Interlocking device to prevent both doors from being opened simultaneously
Light proof
Must also be proof against x-rays
Two compartments – labelled ‘exposed’ and ‘unexposed’ on either side

50. DARK ROOM DRY BENCH SYSTEM
Cassette rack : Stores the loaded cassettes.

53. Hanger storage Stored on metal wall brackets
Each one projects about 230 mm from the wall and can hold max 12 hangers
Two brackets should be placed 100 mm apart from each other
Height of about 750 mm from the workbench

54. Hangers used for suspending films during processing
DIFFERENT TYPES
Channel hangers
Tension hangers
Hanger bars and clips
Tension hangers

55. Channel hangers

57. The darkroom sink Placed adjacent to the processing unit
Sink should be about 250 mm deep, and 750 x 450 mm in its other dimensions.
Hot and cold water should be supplied
Taps should be at least 400 mm above the sink
Cupboards under the sink for storage of equipments and chemical stocks

59. Film Drier Films are hung in their hangers Fan for circulating air
Heater elements to warm the air
Drip tray is provided beneath
Interior safelight
Thermal film bin

60. A well planned darkroom should have following characteristics:
Separation of dry and wet sections.
Orderly sequence of events.
Neat layout of the equipment.
Clear ‘traffic lanes’ for the technicians.
Dry bench
Processing unit
Sink
Drier
Door

61. HEALTH AND SAFETY IN THE PROCESSING AREA

62. ELECTRICAL SAFETY
GENERAL SAFETY
CHEMICAL SAFETY

63. ELECTRICAL SAFETY
All electrical equipments to be sited well away from sinks & manual processing units
Adequate earthing of all electrical appliances
No trailing cables from appliances
Pull-cord switching for lights

64. GENERAL SAFETY MEASURES
The maximum level of safelighting consistent with film sensitivity
Adequate ventilation
Second exits for fire safety
Staff should be advised to read product labels & mixing instructions before handling solutions

65. Thank you !

66. Safelight tests