Systems, devices, and methods for determining and displaying operational parameters of a light fixture that includes narrow band emitters. A controller includes stored information related to spectral power distributions of each of a plurality light wavebands generated by a plurality of narrow band emitters (e.g., LEDs). Based on the spectral power distributions, the controller is configured to determine an output spectrum of the light fixture and/or an output spectrum of individual wavebands. The controller is configured to generate an output display that includes the determined operational parameters associated with the light fixture and a mechanism for manipulating the outputs of the light fixture's wavebands. Using the mechanism, a user can manipulate the operational parameters of the light fixture and observe from the output display a substantially real-time representation of the operational parameters of the light fixture based on the user manipulations.