Darkroom Equipment-
- Light-tight room
- Film cassettes
- Both safe-light and white-light illumination
- Processing tanks
X-ray processing solutions
- Washing Tank & Hot and cold running water
- Accurate thermometer and interval timer
- Dry Bench
- Wet Bench
- Drying racks or dryer
- Adequate storage space
- A radiograph viewer
Light-tight room design-
Dark room design explained in detail in previous post
Film Cassettes-
A film base, an active emulsion layer, a substituting layer of adhesive, and a protective super-coat make up radiographic film.
A cassette is a metal container that is light-tight and made to carry both intensifying screens and x-ray film in close proximity to one another.
Screens and cassettes are of course produced in a variety of sizes to match typical film sizes.
The front face, which is made of aluminium or plastic and faces the tube, has a layer of lead on the other side to absorb back-scatter.
The X-rays are transformed into light by intensifying screens, which creates the picture on the film. As a result, less exposure will be required to provide a diagnostic picture.
Developer and fixer are used to transform the latent picture into a lasting visible image.
It is important to regularly renew and replace the chemicals used in processing.
To maintain top-notch diagnostic pictures, maintenance and quality control are crucial.
Both safe-light and white-light illumination-
Incandescent lighting fixtures that are surface-mounted should emit a bright, white light. If fluorescent lights are turned off right before unloading or loading films, the films may become fogged. Fluorescent lights have a tendency to create a long afterglow. Because they let light to enter the space from above the ceiling area, recessed lights (pot lights, downlights) should not be used. Any penetrations must be sealed if a pot lamp or typical recessed fluorescent lighting is used, and a fireproof box must be created above the ceiling to accommodate the fixture.
And second safe light, The phrase “safelight” in photography refers to darkroom lighting that, when handled and processed properly, does not alter light-sensitive material visibly. Safe is a relative term. The maximum suggested bulb size for direct safe lighting is 15 watts, however indirect safe lighting can utilise 25 watt bulbs. It is crucial to confirm the current safelight wattages with the supplier of the picture because certain movies call for substantially lower power ratings than these values.
Processing tanks and / automatic processor-
The developer and fixer solutions, as well as water for rinsing and cleaning the films, are kept in the processing tank.
Since they deteriorate with usage and time, the developing and fixing solutions should be replaced on a regular basis.
The easiest and most effective method for accurately controlling temperature while developing, rinsing, fixing, and washing films is tank processing. The fresh water tank has a crucial function:
Temperature control and the removal of the developer’s alkali (Na2 CO3) and fixer solution’s acid (acetic)
Keep in mind that these substances might harm your skin and clothes. If you spill any chemicals on your hands, quickly rinse them.
Most darkrooms will have the developer in the left tank, the water bath in the middle, and the fixing solution in the right tank as you face the tank. The developer may be distinguished from the fixer by its vinegary odour when fresh and acid taste (alkali), as well as by its soapy texture. More X-rays will penetrate a region of lower density, like the pulp, hence more X-rays will hit that section of the film. In order to give the pulp chamber a black or radiolucent outline, more silver will precipitate and activate silver bromide crystals.The X-ray film is a fragile product that is susceptible to a variety of factors, including pressure, different gases and fumes, heat, moisture, and even age, which produces a gradual change in the film known as fogging.
X-ray processing solutions-
For the following reasons, developing temperature 68 degrees Fahrenheit (20 degrees Celsius) for 5 minutes is advised:
- The optimum quality of radiographs are attained at this temperature. The contrast and density of the film are most satisfactory and fog is kept to an acceptable low level.
They operate too quickly above 75 degrees Fahrenheit and could cause the film to fog.
Washing Tank & Hot and cold running water-
Washing should be done in 68° F running water. A 20 minute wash is sufficient.
When washing films, the washing tank should be at least four times bigger than the developer tank and have a continuous supply of cold water flowing through it via a rubber hose.
A temperature controller that can pump out 4 to 7 gallons of water per minute can control the water’s temperature.
The typical need to maintain the standard temperature of 20°C is a water chiller that will reduce the water to around 10°C and a heater that will raise it to roughly 60°C. For the needed water supply, the heater and chiller must have the appropriate sizes. (Size determination is dependent on the water temperature and circumstances in the area.)
Accurate thermometer and interval timer-
The temperature of the chemical solutions affects how long it takes for the film to develop. An essential processing-room tool is a thermometer. A tank thermometer (or a floating variety) should be clearly labelled with both Centigrade and Fahrenheit scales. It should also include a steel clip that may be used as a hook to suspend the thermometer in the tank. Using the given thermometer, check the developer’s temperature in the morning and the afternoon.
ii) To regulate the time of development and fixation, an interval timer is also crucial.
Dry Bench-
Along wall , directly across from the sink, is a sizable “dry bench” for cutting plates, filling and emptying plateholders, and possibly even microscopically inspecting the dry, processed plates. The proximity of the bench to the sink facilitates easy transfer of plates from bench to sink, where they are placed in the developer.
The top of the dry bench must be big enough to fit the biggest cassette that is currently in use when it is spread out.
The processing frames should hang above the dry bench , cash size on its appropriate. There are two designs of processing frame– the channel type and the clip type.
Either wood or linoleum should be used for the top surface. Because plastic laminates retain electrical static charges that might leave markings on films, they are not advised.
Wet Bench-
For the safe drying of processed plates, there is a “wet bench” available to the right of the sink.
The typical technique involves using a series of tanks to contain developer, rinse water, and fixer, as well as a bigger tank to wash the films.
Adequate storage space –
It is on the dry bench.
A location to store chemicals and films is necessary. Processing rooms are not permitted to be used for storage or for any dental office practise that can contaminate the films with dust or odours. The darkroom, however, shouldn’t be used as a general storage area.
Film boxes, especially those that are currently in use, are often kept beneath the dry bench, either in a film hopper or a cabinet that is shielded if it is next to an X-ray machine.
Drying racks or dryer-
By taking the film from the channel hanger, fastening a film clip, and hanging it on a tensioned wire set up in a dust-free location, films may be dried.
If drying and development are done in the same space, it is advised to have some type of ventilation system in place to remove heated dryer air while also bringing in fresh air. Where an automatic dryer is not present, there should be suitable drying racks.
radiographic viewer-
When using wet viewing, time temperature, or other darkroom procedures, a radiographic viewer is utilised to observe the finished image and assess the process.
The typical way to examine radiographs (developed film exposed to x-ray or gamma radiation) is on a light box.
It’s crucial to have the right viewing circumstances while reading a radiograph. The way you examine radiographs can improve or hurt their fine features.
