Lesson 2.2 Flashcards
Proper illumination in a darkroom is essential to facilitate safe film handling while preventing unwanted exposure that could damage image quality
Darkroom Illumination
There are 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.
White Light
Typically consists of fluorescent bulbs or
small incandescent bulbs that provide
bright light when necessary.
White Light
White light placement consideration
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.
Provides low-intensity illumination that allows technicians to handle films
safely without causing fogging
Safelight
A lamp housing with a 15- watt bulb and a 6B filter is typically used.
Safelight
Safelight 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:
Used for blue-sensitive films (calciumtungstate screens).
Amber filter
It transmits wavelengths longer than
550 nm.
Amber filter
Used for green-sensitive films (rare-earth screens)
Red Filter
It transmits light above 600 nm, preventing fogging
Red Filter
What are the types of safelight
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
Mounted above and to the rear of the
processing tank to check film while in the fixer solution.
Wet Film Illuminator
Used during the hardening and
washing stages of processing to inspect
film progress
Wet Film Illuminator
Wet Film Illuminator 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.
Walls and ceilings should be painted with non-reflective paint to prevent light from bouncing and unintentionally
exposing the film.
Wall Finish Illuminator
If a safelight emits slightly high-intensity
spectral quality light, it may interact with
reflective surfaces, potentially causing
unintended film exposure
Wall Finish Illuminator
Using dark, matte-finished paint reduces this risk and maintains a controlled lighting environment.
Wall Finish Illuminator
ensures efficient workflow while protecting radiographic films from
accidental exposure. Each type of lighting has a specific purpose, and its correct installation and
usage are essential to maintaining high-quality radiographs
proper darkroom illumination
For maintenance
activities
White Light
For safe film handling
Safelight
For checking films in
fixer
Wet Film Illuminator
Prevents light
reflection
Wall Finish
