As the name implies, a timer is what controls the length of an exposure. A timer can be something as simple as a watch or as complex as a high-end multi-functional digital timer. The advantage of an electronic timer is that it can be connected to the enlarger’s lamp house and will automatically turn the enlarger lamp on and off when you press the PRINT button. Timers can be analog or digital. The old-style analog timers are tried and true. They usually have a sweep dial with easy-to-read, sometimes glow-in-the-dark numbers.
To use, just turn the sweep hand to the number of seconds you want, press the PRINT button, and the timer starts the process. The enlarger kicks in, the negative is exposed and when the timing cycle is over, the timer turns the enlarger off. A good timer will have two inputs. One is for the enlarger and the other is for the safelight. In addition to turning the enlarger on and off, the timer will turn the safelight off and on during and after the exposure. Most analog timers tell time in full seconds with little space for tweaking the exposure between numbers. Analog timers are also very good for developing negatives. The large numbers are easy to read while you’re mixing chemicals or processing film.
On the other hand, digital timers are much more accurate. A digital timer usually reads out in LEDs. Like their analog siblings, they can also control the safelight. However, digital timers are designed to perform other functions as well. Some can control more than one machine at a time, or change the display from full seconds to tenths of seconds. Some printers feel that that the accuracy of a digital timer is offset by the small size of the buttons, which can be difficult to see and use under a safelight. Conversely, analog timers, although easier to use, are not as pinpoint accurate—particularly if your exposures require fractions of seconds. The reality is that both serve a purpose in your darkroom.
A fully stocked darkroom has more than one timer: one for exposing the print, another for timing the development, and on occasion, a third one for timing a wash. Once you become adept at printing, you will find that you can run several operations simultaneously, i.e. printing, developing and washing.