Chapter 10: Film Processing

Reduction (film)

A chemical reaction occurs when film is placed in the chemical solutions.

Latent Image

The pattern of stored energy on exposed film.

Radiolucent

Readily permits passage of the x-ray beam and appears black.

Radiopaque

Resists passage of the x-ray beam and appears white or radiopaque.

What are the 5 steps in manual film processing?

1. Developer solution

2. Rinsing

3. Fixer solution

4. Washing

5. Drying

What is the purpose of developer solution?

Reduces the exposed, energized silver halide crystals into black, metallic silver and softens the film emulsion.

What is the purpose of rinsing in the manual film processing?

Stops the development process.

What is the purpose of fixer solution?

Removes the unexposed, unenergized silver halide crystals from film and hardens the film emulsion.

What is the purpose of washing the manual film?

Removes all excess chemicals from the emulsion.

What is the purpose of drying in the manual film processing?

Films must be dried before they can be handled for mounting or viewing.

How often do film processing solutions need to be changed?

3-4 weeks

What are the components of developing agents?

• Hydroquinone

• Elon

• Preservative

• Accelerator

• Restrainer

What are the components of fixing agents?

• Fixing agent (sodium thiosulfate or ammonium thiosulfate)

• Preservative

• Hardening agent

• Acidifier

What is the optimal temperature for the developer solution?

68F or 20C

What are some issues from an exhausted developing solution?

Depletes from evaporation and removal of small amounts while in use. Exhausted developer does not fully develop the latent image.

What are some issues from exhausted fixer solution?

Depletes from evaporation and removal of small amounts. Diluted each time water is transferred from rinse. Exhausted fixer does not stop the chemical sufficiently.

What are the advantages of automatic film processing?

• less processing time required

• time and temperature automatically controlled

• less equipment used

• less space required

What are disadvantages of the automatic processor?

• May be limited to certain sizes of films

• May require a darkroom

What is the advantage to a daylight loader?

Can be used in a room with white light.

What are the 5 components of the automatic processor?

1. Uses a roller transport system to move dental x-ray through developer, fixer, water, and drying compartments.

2. Processor housing

3. Film feed slot

4. Roller film transporter

5. Developer compartment

T/F You can use automatic processing solutions in manual developers.

F, never use automatic processing solutions in manual developers.

What is a reference radiograph?

• Processed under ideal conditions using a step wedge

• Prepare the film

• Expose film using correct exposure factors

• Use fresh chemicals at the recommended time and temperature

• View the reference radiograph and daily radiogrpah side by side on a view box to determine the quality

What is the purpose of a darkroom?

• Provides a completely darken environment where x-ray film can be handled and processed.

• Must exclude any visible white light “light-tight”

• White light leaks and will cause film “fogging” will appear gray, lacks contrast and nondiagnostic.

What is used to provide light in a darkroom?

A safelight is used which is a special type of lighting to provide illumination in the darkroom.