(2) At least four heavy, durable, white enamel trays are essential. They
should be of adequate size to accommodate the largest film normally exposed. One
tray each is used for developer solution, rinse water or stop bath, fixing solution, and
wash water. The tray used for washing should be fitted with an automatic tray siphon
so that the water will be kept in constant circulation.
(3) A quantity of developer and fixing solution should be mixed at regular
intervals and kept in brown bottles. Enough solution to cover the film at least one inch
is poured into the proper trays just before processing. The temperature of the solutions
should be 68F. Only one film should be developed at a time and care must be taken to
ensure that the softened emulsion is not scratched during development, and it does not
stick to the bottom of the tray. The method requires somewhat less time than tank
processing because of the constant agitation of solutions in trays, which is essential in
b. Procedure. Assuming that the solutions are ready and at a temperature of
68F, the steps in the processing procedure are as follows:
(1) On removing the film from the cassette or exposure holder, attach a
dental x-ray film clip to one corner to facilitate handling. Immerse the film in the
developer solution with a quick sliding motion so that it is completely covered. Unduly
slow and uneven immersion will result in a dark line on the radiograph.
(2) Start the timer for the proper interval as indicated by the temperature
and activity of the solutions. Because of the more or less continuous agitation afforded
by this procedure, it requires 20 percent less development time than the tank system.
For example, using rapid developer and a basic three-minute development time at 68F,
normal contrast is provided in screen-type film with a 2-1/2-minute tray development.
During development, the film must be moved about frequently so that the underside
does not adhere to the tray and thereby retard the action of the developer on the
emulsion. It is also advisable to turn the film over several times during development.
The tray should be rocked to provide continuous redistribution of solution over both
surfaces of the film. This agitation can be accomplished by raising and lowering
alternate sides of the tray and must continue throughout the processing period.
(3) Rinse the film in fresh water or acid bath for 20 seconds and transfer it to
the fixing solution for 15 minutes. When the film is first placed in the tray, and at
intervals during fixation, the solution should be agitated by the method previously
described. The film must not be allowed to rest on the bottom.
(4) After fixing, the film should be washed in running water for not less than
20 minutes. The rate of flow should be rapid enough to replace the water in the tray at
least eight to 10 times an hour. If several films are developed in succession, the
washing time must be calculated from the time the last film was placed in the wash