DARKROOM ILLUMINATION Flashcards
Proper illumination in a darkroom is essential to
facilitate safe film handling while preventing
unwanted exposure that could damage image
quality. There are four primary types of
illumination used in a radiographic darkroom:
DARKROOM
ILLUMINATION
four primary types of
illumination used in a radiographic darkroom:
WHITE LIGHT
safelight
Wet film illuminator
wall finish illuminator
- Used for general
maintenance activities
such as cleaning the
room, washing tanks,
mixing solutions,
placing film in the
dryer, and unloading
films from hangers. - Typically consists of
fluorescent bulbs or
small incandescent
bulbs that provide
bright light when
necessary.
3.Placement Considerations:
White light should be kept away from the film
storage area to prevent accidental exposure.
It should only be turned on when no films are
being processed to avoid film fogging.
White light
1 Provides low-intensity
illumination that allows
technicians to handle films
safely without causing
fogging.
- A lamp housing with a 15-
watt bulb and a 6B filter is
typically used. - Placement Guidelines:
Safelights should be mounted on the top of the dry section at
a minimum distance of 5 feet from the work surface.
The filter type used depends on the film’s sensitivity:
Amber filter: Used for blue-sensitive films (calcium-
tungstate screens). It transmits wavelengths longer than
550 nm.
Red filter: Used for green-sensitive films (rare-earth
screens). It transmits light above 600 nm, preventing
fogging
Safelight
Types of Safelights
DIRECT TYPE
INDIRECT TYPE
Mounted on the dry side, emitting light directly
toward the work area.
Direct Type
Mounted so that the light is directed toward the
ceiling, allowing for reflected light to illuminate
the darkroom gently.
Indirect Type
1 Mounted above and to the rear of the
processing tank to
check film while in the
fixer solution.
- Used during the
hardening and
washing stages of
processing to inspect
film progress. - Precautions:
Must be turned on only when necessary.
Ensure that no open box of film is on the dry side
and that no film is under the developer solution or
stop bath before switching it on.
Wet Film Illuminator
1 Walls and ceilings
should be painted with
non-reflective paint to
prevent light from
bouncing and
unintentionally
exposing the film.
2 If a safelight emits
slightly high-intensity
spectral quality light,
it may interact with
reflective surfaces,
potentially causing
unintended film
exposure.
3 Using dark, matte-finished paint reduces this risk
and maintains a controlled lighting environment.
Wall Finish Illuminator
For maintenance
activities
White Light
For safe film handling
Safelight
For checking films in
fixer
Wet Film Illuminator
Prevents light
reflection
Wall Finish
Proper ventilation is essential in a radiographic
darkroom to create a comfortable working
environment for radiologic technologists while
maintaining film quality and chemical stability.
DARKROOM VENTILATION
Importance of
Ventilation
- A well-ventilated darkroom helps maintain a
conducive atmosphere, making film processing more
efficient. - Proper air-conditioning protects films in storage and
prevents the evaporation of processing chemicals,
which can affect film development.
Humidity Control
40-60%
1 Above 60%: Leads to reduced contrast and increased
fog in radiographs.
2 Below 40%: Increases the risk of static artifacts,
which appear as unwanted marks on the film.
Temperature Regulation
19.44-20°C 10°C
(67 degree F - 68 degree F)
High temperatures reduce image contrast
and increase film fog.
(50 degree F)
A film could be stored for a long period if
the temperature maintained.
10°C
Airflow Requirements
15-25 FT/MIN
1.Air movement in the darkroom should be maintained at 15 to 25 feet
per minute to prevent chemical vapor buildup.
2.Positive air pressure should be maintained inside the processing
room to prevent dust and external contaminants from entering
Exhaust System and
Air Filtration
The film dryer should have
a separate duct leading
outside the darkroom to
remove excess heat and
humidity.
Dryer exhaust:
Incoming air should pass
through filters to remove
dust particles, preventing
contamination of film and
chemicals.
Filtered air intake
is
where the initial handling of films occurs, including loading and unloading of cassettes and film
hangers. This section must be well-organized to prevent film damage and exposure to unwanted
light.
Dry Section
DRY SECTION
COMPONENTS
loading bench
film bin
storage of hanger
storage compartment
cassette transfer cabinet (pass box)
waste receptacle
storage cabinet
1 The primary workspace for handling films.
2 A small table, typically 28 inches long and 17 inches
wide, though size may vary based on darkroom
dimensions.
- Used for loading and unloading films into cassettes
and hangers.
4 Height: Must be 3 feet for comfortable use.
Loading Bench
