The document provides a comprehensive overview of darkroom construction and design principles for radiology departments, highlighting the importance of processing areas, both daylight and darkroom options. It details critical elements such as location, size, radiation protection, ventilation, and equipment necessary for effective film processing. Additionally, it emphasizes safety procedures related to electrical, chemical, and general hazards within darkroom environments.

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DARKROOM
CONSTRUCTION
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2. General introduction
• The latent image formed in the phosphor crystals
after the exposure, has to be converted into the
visible form. The place where this can be achieved
is called processing area.
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3. Types of processing area
1.Daylight processing
2.Darkroom processing
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4. History
In the past ,the processing area was
synonymous with a darkroom /viewing area.
But the event of daylight processing systems in
1970 and 1980 and the electronic imaging
systems in 1990 has dramatically changed this
area. So now a days in all the radiology dept.
darkroom has been replaced by daylight area.
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5. Location of processing area
• It should be close to the radiography rooms which
minimizes the no. of processors required,saves the
time and effort spent walking from imaging room to
the processor.
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x-ray room
2
Cassette
hatch
x-ray room
3
x-ray room
1
Darkroom
X- ray room
4
Automatic
processor
Viewing area
Film sorting
Fig.2. Plan view of a four- room department serviced by one
darkroom/viewing area.

7. Viewing area
• Where viewing, checking and sorting of films is
done
• Should be out of the sight and sound of patient
• Cassette storage racks, vertical compartments
under the worktops
• Viewing boxes and spotlights
• Site of intense activity so requires more space
to accommodate both high occupancy and staff
movements
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8. Darkroom design /construction
1.Location
2.size
3.Radiation protection
4.Floor
5.Walls
6.Ceiling
7.Ventilation/heating
8.Entrance
9.Cassette hatch
10.Layout
11. Illumination
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9. 1. Location
• Centrally located to the radiodiagnostic rooms
• Should not be in hot or damp places
• Should be protected from radiation
• Should be accessible to electricity and water
supply
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10. 2. Size
• Rectangular
• Distance between dry and wet bench should 4 or 5ft
• Minimum size of room is 100sq.m of floor.
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11. 3. Radiation protection
• The radiation from adjoining radiodiagnostic
rooms must be protected adequately
• To check the leakage of radiation TLD should be
left in place for at least a week
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12. 4. Floor
• It must be about 10 square meter.
• It must be non porous , made of non slip flooring
material.
• Must be Resistant to staining by chemicals.
• Must be waterproof, chemical proof, stain proof
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13. 5. Walls
• Must be light in color
• Must be easy to wipe over and keep clean
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14. 6. Ceiling
• Ceiling height should be about 10feet (2.7m high)
• Must be light in color ,easy to wipe over and keep
clean
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15. 7. Ventilation/heating
• Air should change 10-12 times per hour
• Humidity is maintained about 40-60 percent
• Temperature- 65-68 F(18-20 c) which must be maintained
by ordinary hot-water radiator.
• Purpose of Ventilation/heating are for satisfactory
working condition for staffs, good film handling and
storage condition and efficient automatic processor
performance
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16. 8. Entrance
• Necessarily of special design
• Must be of light tight
• Four special designs are available
a) Single door system
b) Double door system
c) Labyrinths
d) Rotating door system
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17. 8. a) Single door system
– Capable of totally exclude light
– Can not be opened during film handling
– Latch or lock from inside, capable of releasing lock
from outside in case of emergency
– Relatively inexpensive and economical
– Problem for multiple darkroom operator
– Sliding door is more preferred
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fig. single door system

19. 8. b) Double door system
• More benefited than single door in term of light
• Electrical inter lock can be used
• Safer from occurring the accident
• Need more area
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21. 8. c) Labyrinths/maze type
entrance
• Consists of two parallel passages of 700 mm each
and facing wall
• A malt black paint for anterior facing portion of
the door
• Vertical height is about 2 m
• Length is about 3 m
• Easy entrance to the darkroom ,no hazards to a
single handed operator
• But requires relatively more space
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24. 8.d)Rotating door system
• Employs metal cylinder with an opening in its side
for entry and exit
• Manual rotation of cylinder facilitates for the entry
and exit the dark room
• Does not required large floor area for installation
• Most reliable but some risk of occurring accident
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25. Fig: Rotating door
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26. 9.Cassette hatch
• Must have interlocking system
• Must have lead lined about 2mm
• Size is adjusted for every cassette
• Must be in centre between dark room and x-ray
room
• Must be radiation and light protected
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28. 10.Illumination
• It is used to light the room
• To prevent the staff from electric shock
• For the controlling of mishandling of films
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29. Illumination types
1.General white light
2.Safe light
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30. General white light
1.For inspection & maintenance of cassettes and screens
2.For cleaning of work surfaces & floors
3.Required for servicing of equipment
It should be:
• close to the ceiling to avoid casting of strong shadows
• moderate in intensity
• centrally placed
• Moderate in intensity (60 w tungsten or 30 w fluorescent)
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31. 2.Safe light illumination
• for easy or pleasant working conditions
• Should be dim,coloured, provide sufficient
illumination by which one can
handle,manipulate & process film
• but "there is no totally safe lighting.
• Should not more than 25 watt
• No near than 4 ft(1.22m) from working bench
• Uses Colored filter to alter the color of safe light
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Safelight filters:
 consist of gelatin dyed to the appropriate
colour,sandwiched between two sheets of glass for
protection.
 Gelatin will deteriorate if subjected to extremes of heat
& moisture & so higher- wattage lamps should never be
used.
coloured gelatin layer
plain or clear glass
diffusing glass
fig:Cross-section through a safe light filter

33. Safe light color
• Depends on the types of emulsion used in
the film
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34. Monochromatic emulsion
• Sensitive to blue portion spectrum
• So safelight should green , red or
brown
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35. Orthochromatic emulsion
• Blue green sensitive film
• Safelight color is red
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36. Panchromatic emulsion
• Sensitive to all color
• No safelight is used
• Dark green safelight can be used to view
the timer
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Note: Panchromatic film present special problems since it will have color
sensitivity extending as far as the end of the spectrum .It is thus advisable
to process such film in complete darkness.

37. Spectral transmission graph
• A graph produce for their safe light
• Indicates part of visible spectrum which will
transmitted by the filter
• Helps in Matching of appropriate filter to the
type of film in use
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38. • Fig1. safelight filter suitable for use with monochromatic film materials. Producing greater
filter transmission is in the 55o nm wavelength range
• Fig2. filter which can be use with orthochromatic film
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39. Safe light and its safety
• Actually no safe lighting is completely safe
• Safelight filters are not perfect absorbers
• All film have some sensitivity to all wavelengths
• So intensity of illumination and film-handling time
must be kept to a minimum
• Sensitivity of exposed film is far greater to
safelight than unexposed materials results in
fogging
• Safelight can not cross the threshold level for the
unexposed films so less fogging effect
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40. Safelight testing
• Whenever using a new darkroom
• Where safelight has been changed
• If faster film material is introduced
• Suspected leakage of safelight fogging
• For quality assurance
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41. Darkroom equipment and its
arrangement
1. An automatic processor
2. Cassette hatch or hatches
3. Film storage hopper
4. Loading bench / cupboards
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Automatic film processor:
 plan only the feed tray inside the DR.
Cassette Hatches;
 interlocking device, to prevent light leakage.
 two compartments: one for exposed & another for unexposed
cassettes.
 Allow easy transport of film cassettes between radiographic
rooms & DR.
 one door of the hatch is lined with 2mm thickness of lead.
 need to open directly in to a radiographic room.

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Film hoppers:
 each film hoppers compartment
accommodates different sized films.
 light- tight
 This is to link electronically the film hopper
microswitch with white lighting circuit so that
the white light goes off if the hopper is
inadvertently opened.

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Loading bench/cupboards:
 should consist of a workbench & generous
cupboard space.

48. Safety in processing areas
• Electrical
• General
• Chemical
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49. Electrical
:
– Electrical equipments away from sinks and manual
processing area
– Electrical appliances adequately earthed
– Pull-cord switching for light
– No trailing cables from appliances
– Pilot lamps incorporated in equipment
– Isolator switches
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50. General
• Concern with film sensitivity
• Adequate ventilation
• Second exits for fire safety
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51. Chemical
• Toxic chemicals have to be handle with care
• Should be aware of harmful effect of those
chemical
• Due to their chemistry ,effect through
inhalation ,ingestion or skin contact
• Better if follow the COSHH principal
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Control of Substances Hazardous to
Health(COSHH)
It impose a responsibility upon managers to ensure that the
following procedures are carried out in their departments.
a) health risk assessments undertaken in order to determine
with hazards ,if any,exist. necessary precautions decided.
b) control measures introduced to minimize or eliminate
identified risks.
c) if deemed necessary, health surveillance undertaken for
early detection of illness due to occupational exposure.
d) adequate information, instruction & training afforded to all
key staff.