development timer

Developing photographic films can be something of a chore. Not only is it necessary to measure the total development time, but it is also necessary to ~gitate the development tank at frequent intervals to ensure even development of the film. This means that the clock must be watched continuously. The development timer described in this article overcomes these problems by measuring the intervals at which and the length of time for which the tank must be agitated, as well as the total development time.