Film cassettes have a phosphor screen in contact with the film that enhances
the transfer of the x-ray image to the film. The presence of dirt, dust, and
oils on the screen will interfere with the creation of the image. Screens should
be inspected and cleaned regularly with the cleaning solution recommended by the
To obtain the optimal image quality, it is imperative that the darkroom is
free of dirt and dust, is adequately light-tight, and that proper safelight
procedures are followed. The National Committee on Radiation Protection suggests
the following procedure to determine if an adequate light seal exists:
- Turn off all lights in the darkroom, including the safelight.
- Place a small coin on top of an unwrapped intra-oral film for five
- Develop the film.
If a shadow of the coin is seen on the film, additional measures should be
taken to improve the light seal of the darkroom.
Safelights must be compatible with the film being used. If they are not,
fogging of the film may reduce the quality of the x-ray images. To test
compatibility of film and safelights, repeat the above darkroom film fogging
test with the safelight on. No shadow should be evident on the film.
Grids are used for thick body parts in general radiography and fluoroscopy to
reduce the amount of scattered radiation reaching the image receptor. This will
increase the contrast of the image and improve the physician's ability to
provide an accurate diagnosis. Grids are not routinely used in dental