10.2

Manual film processing requires equipment accessories, step-by-step procedures, and care and maintenance. Manual film processing is commonly used to develop working endodontic films quickly. Manual film processing is also known as “hand processing” or “tank processing.”

The steps for manual film processing are development, rinse, fixation, washing, and drying.

Film Processing Solutions

Film processing solutions may be obtained as powder, ready-to-use liquid, liquid concentrate or powder, and concentrate requires distilled water added to it, which most practices don’t take time to do and results in films being overdeveloped. The ready-to-use liquid is by far the most commonly used solution.

In the Iannucci & Howerton, Dental Radiography Principles & Techniques, 6th Edition textbook on page 93, refer to Figure 10-5.

To maintain the freshness of film processing solutions, they must be replenished daily, changed every 3 to 4 weeks, and may need to be changed more frequently when large numbers of films are processed.

Developer Solution

The developing agent is hydroquinone, which has black tones and sharp contrast, and elon, which are shades of gray.

Preservative―sodium sulfite, accelerator―sodium carbonate and restrainer―potassium bromide are involved. The purpose of the developer is to chemically reduce the exposed silver halide crystals to black metallic silver. The developer solution also softens the film emulsion during this process.

In the Iannucci & Howerton, Dental Radiography Principles & Techniques, 6th Edition textbook on page 93, refer to Figure 10-1.

Fixer Solution

The fixing agent is Sodium thiosulfate or ammonium thiosulfate and is commonly called “hypo.”.

Preservatives―sodium sulfite, hardening agent―potassium alum, and acidifier―acetic acid or sulfuric acid are involved. The purpose of the fixer solution is to remove or clear all unexposed and underdeveloped silver halide crystals from the film emulsion.

In the Iannucci & Howerton, Dental Radiography Principles & Techniques, 6th Edition textbook on page 94, refer to Figure 10-2.

Equipment Requirements

Equipment required for film processing is a processing tank, an automatic processor, and manual film processing equipment, including a processing tank and related equipment accessories.

In the Iannucci & Howerton, Dental Radiography Principles & Techniques, 6th Edition textbook on page 95, refer to Figure 10-7.

Processing Tank

The processing tank is manual processing and hand processing. A processing tank is required for manual processing and is divided into compartments to hold developer solution, water bath, and fixer solution.

Mineral salts in water and carbonate in processing solutions produce deposits on the inside walls of the insert tanks. The tanks must be cleaned with commercial cleaner or hydrochloric acid when the solutions are changed. Abrasive-type cleansers are not recommended for cleaning processing tanks as they can interfere with the processing solutions.

In the Iannucci & Howerton, Dental Radiography Principles & Techniques, 6th Edition textbook on page 95, refer to Figure 10-6, and on page 98, refer to Figure 10-3.

Insert tanks are two tanks to hold developer and fixer solutions, and both fit into a master tank. A master tank suspends both insert tanks and is filled with circulating water. The mixing valve controls the water temperature. A developer is usually placed in the insert tank on the left, and the fixer solution is on the right. An overflow is used to control the water level in the master tank. The optimum temperature for a water bath is 68 degrees Fahrenheit.

Equipment Accessories

The equipment accessories needed for film processing are a thermometer, which is placed in the developer solution, a timer to indicate processing time intervals, film hangers that are needed for drying films, and other miscellaneous equipment like stirring rods that mix chemicals and equalize the temperature.

In the Iannucci & Howerton, Dental Radiography Principles & Techniques, 6th Edition textbook on page 96, refer to Figure 10-8.

Step-by-Step Procedures

Here are the following steps for manual film processing:

1. Identify the solutions
2. Check solution levels
3. Stir the solutions
4. Check the temperature of the developer solution
5. Label film hanger
6. Prepare the darkroom
7. Unwrap the films
8. Load the hanger
9. Set the timer
10. All steps must be followed with correct infection control procedures.
11. Immerse the films and activate the timer
12. Remove the films from the developer and rinse
13. Determine the fixed time
14. Immerse the films and activate the timer
15. Remove the films from the fixer and place them into the water wash
16. Dry the films
17. Be careful not to scratch the films when clipping them on the film hanger
18. Remove the films from the rack
19. Clean up

In the Iannucci & Howerton, Dental Radiography Principles & Techniques, 6th Edition textbook on page 97, refer to Figure 10-2.

Care and Maintenance

The processing solutions, processing tank, and miscellaneous equipment accessories are used in manual processing and must be carefully maintained.

Processing Solutions

For processing solutions, it is essential to follow the manufacturer’s instructions for storage, mixing, and use. Solutions deteriorate with exposure to air, continued use, and chemical contamination. Exhausted processing solutions result in non-diagnostic images and must be replaced.

Miscellaneous Equipment

Miscellaneous equipment for manual processing includes film hangers, stirring paddles, and a plastic apron. Film hangers and stirring paddles must be cleaned after each use.

In the Iannucci & Howerton, Dental Radiography Principles & Techniques, 6th Edition textbook on page 96, refer to Figure 10-8.

The Darkroom

The darkroom is a completely darkened environment within which x-ray film can be handled and processed to produce diagnostic images. It must be properly designed and equipped. Leaks in the darkroom, as well as the film left in the x-ray room after the initial exposure and exposure to background radiation, may cause a fogged film. Remember to keep exposed films outside the radiography operator.

A darkroom workspace must also include an adequate counter area where films can be unwrapped, kept clean, dry, and free from processing chemicals, and a container for biohazards should be available and labeled. The darkroom storage space has to have a humidity level and darkroom plumbing.

Room Requirements

Room requirements are as follows:

• Conveniently located
• Adequate size
• Equipped with correct lighting
• If the developing room is not light tight may cause film-fog
• Arranged with ample workspace with adequate storage
• Temperature and humidity controlled
• If the developer solution is too warm, it may cause an overdeveloped film (too dark)

Location Sizes

The location should be near where x-ray units are installed and should be large enough to accommodate film processing equipment, allow an ample workspace, and be clean at all times. The size can be determined by the volume of film processed, the number of persons using the room, the type of processing equipment used, the space required for duplication of films and storage, and a darkroom should measure at least 16 x 20 square feet and provide one person to fit comfortably.

Lighting

Waste Management

Film Duplication

Film duplication has it’s own equipment requirements and step-by-step procedures as well. An identical copy of an intraoral or extraoral dental image is made through the process of film duplication.

Equipment Requirements

For a film duplicator, a commercially available light source and duplicating film is required. Unlike intraoral film, duplicating film has a single emulsion layer and is never exposed to x-rays—only to light.

In the Iannucci & Howerton, Dental Radiography Principles & Techniques, 6th Edition textbook on page 99, refer to Figure 10-11.

Step-by-Step Procedure

The film duplication steps are as follows:

1. Arrange the original set of processed film in anatomic order
2. Place duplicating film
3. Secure the duplicator lid
4. Set the timer
5. Process the duplicating film
6. Label the duplicate image
7. The duplicating machine produces white light to expose the film.
8. Because the film is light-sensitive, the duplication process is performed in the darkroom under the safelight.

In the Iannucci & Howerton, Dental Radiography Principles & Techniques, 6th Edition textbook on page 100, refer to Figure 10-4.

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• Iannucci & Howerton: Dental Radiography Principles and Techniques, 6th Edition, Chapter 10, CC BY-NC-ND