Dental film processing involves a series of chemical reactions that convert the latent image on an x-ray film to a visible image. There are automatic and manual processing methods. For both, the film first develops the latent image formed during exposure into visible black metallic silver. It is then rinsed, fixed to remove unexposed silver halide crystals, washed, and dried. Proper safelighting and regular replenishment of chemicals is important for consistent, quality results.

1. Dental Film Processing

2. Series of chemical changes brought about
on the image receptor to convert the latent
image to a visible image

3. • Automatic
• Manual
–Visual method
–Time – temperature method

4. Latent image
• X ray photons interact with Silver halide
crystals when irradiated and form
‘LATENT IMAGE’
• Latent image is invisible

5. Latent Image
Many x-rays
penetrate and
expose many silver
halide crystals
Fewer x-rays
penetrate and not as
many silver halide
crystals are exposed
Few, if any, x-rays
penetrate; silver
halide crystals not
exposed
Air/soft tissue Bone Amalgam/gold
= Exposure centers

6. • Developing
• Rinsing
• Fixing
• Washing
• Drying
• Mounting

7. Developer
• Composition
– Developer: Elon (gray shades) and
Hydroquinon (contrast)
– Preservative: Sodium sulfite (prevents
oxidation)
– Activator: Sodium carbonate (maintain
Alkalinity)
– Restrainer: Potassium bromide (prevents
reduction of unexposed crystals

8. Developing…
• Latent image is converted to visible image
• Emulsion swells and gets saturated within
developer

9. Air/soft tissue Bone Amalgam/gold
Developing
Development centers in crystals struck by
x-rays are converted into black metallic
silver

10. Air/soft tissue Bone Amalgam/gold
Developing (continued)
Entire crystal converted to
black metallic silver

11. Rinse
• Water for 15 to 20 seconds
• To stop the process of developing
• Prevent alkali being carried to acid fixer

12. Fixer
• Composition
– Clearing agent: Sodium or Ammonium
thiosulfate (dissolve and remove
unexposed silver halide crystals)
–Acidifier: Acetic acid (Neutralize
contaminating alkali)
–Preservative: Sodium sulfite (prevent
decomposition of thiosulfate clearing
agent)
–Hardener: Aluminum potassium sulfate
(prevent damage to the gelatin)

13. Fixing
• Double the time in the developer
• To remove the unexposed silver halide
crystals
• Harden the film emulsion

14. Air/soft tissue Bone Amalgam/gold
Fixing
In the fixing solution, the unexposed silver halide
crystals are removed from the film by the fixing
solution.

15. Wash
• Wash the film running water
for 10 – 15 minutes

16. Manual Processing

17. Manual Processing
Cold
Hot
Mixing valve
Fixer
insert tank
Developer
insert tank
overflow tube
drain
waterbath (large tank)
water inlet

18. Safelighting
The safelight should
have a 15-watt bulb
(older style safelight)
and be mounted to the
wall or ceiling at least 4
feet from the area where
the films are unwrapped
and loaded into the film
processor.
15 watt bulb
4 feet
red filter
15 W

19. Replenishment
Solutions tend to become depleted.
Results in inadequate developing or fixing
To prevent this, it is important to replenish
the solutions (both developer and fixer)
each day.

20. Film
Exit
Dryer
(heater, fan)
Film
Entry
Wash
Automatic Processor
FixerDeveloper

21. Automatic Processor
insert films
developer
fixer
dryer
wash

22. Daylight Loader
lid
rubber cuffs