Most black-and-white automatic film processors have a variable speed operation. Unlike hand processing where developing time is measured in minutes and seconds, machine processing developing times are measured in feet-per-minute (fpm). Both methods measure the length of time the material is affected by the developer and other solutions. Most color processors have a set machine speed that can only be adjusted slightly because color materials must be processed to specific parameters so processing cannot be manipulated.

The time the solutions are allowed to act on the film or paper is a result of the speed that the machine moves the sensitized material and the length of time the material is immersed in a particular tank. Most machines have an fpm indicator that shows the set speed of the processor. The temperatures of solutions and the specific number of feet in each section of the machine are usually constant factors. It is the rate the paper or film travels that determines the total processing time; for example, if the speed is set to 10 fpm and the total roller

path in the developing tank is 30 feet, a certain point on the material being developed takes 3 minutes (30 10).

Regardless of the machine speed, film or paper cannot be processed faster than the total required solution times. For example, you are processing film that requires a processing and drying time of 10 minutes and 20 seconds. When the machine is processing this film, it takes 10 minutes and 20 seconds before the first foot of film leaves the dryer. However, the total time to process the entire roll is related to the speed of the machine and the total length of the material. For example, if the machine speed is 10 fpm and the roll is 10 feet long, the film takes 10 minutes, 20 seconds, plus 1 minute (10 10). With a 200-foot roll, access time is 10 minutes, plus 20 seconds, plus 20 minutes

(200 10), or a total of 30 minutes, 20 seconds. It is important for you to know the access time of the processor. When the material being processed does not exit the machine in the required time, a machine malfunction or jam is evident.