A lighting device that can generate light of variable color and intensity under processor control. Multiple lighting devices of a modular design can be incorporated into a lighting system to illuminate larger areas. A lighting module includes three groups of LEDs each of which generates light of a different color whose intensity can be controlled. A lighting system can be formed by coupling multiple lighting devices to a central controller comprising an operator interface panel and an interface to an external computer. The external computer can be provided with programming tools that allow the creation of lighting programs for controlling the operation of the lighting system. A user can select programs or modify the operation of the lighting system from the operator interface panel provided at the central controller or from the external computer. Procedures are provided for calibrating the color and power output of each lighting device.