Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

Arresting Development
After development is complete, developer remaining in the emulsion must be
deactivated by an acid stop bath or, if this is not feasible, by prolonged rinsing
in clean running water. If this step is omitted, development continues for the
first minute or so of fixation and, unless the film is agitated almost
continuously during this period, uneven development will occur, resulting in
streakiness. In addition, if films are transferred to the fixer solution without the
use of an acid stop bath or thorough rinsing, the alkali from the developer
solution retained by the gelatin neutralizes some of the acid in the fixer
solution. After a certain quantity of acid has been neutralized, the chemical
balance of the fixer solution is upset and its usefulness is greatly impaired--
the hardening action is destroyed and stains are likely to be produced in the
radiographs. Removal of as much of the developer solution as possible
before fixation prolongs the life of the fixer solution and assures the routine
production of radiographs of better quality.
Charlie Chong/ Fion Zhang
Radiography in Modern Industry. Rochester, NY: Eastman Kodak Co. 1980