The roles, composition and number of workers in a tech crew can change significantly depending on the nature of an event, and often evolves as the production does.
In a small scale production, the technical crew might consist of a single person, operating the lights and controlling the volume of the sounds and music.
In a large scale productions, the technical crew can consist of dozens of different departments and may run into the hundreds of individuals.
The nature of most productions result in the technical crew being on-site for significant periods of time; both leading up to and after a performance.
Most often, though not exclusively, members of the technical crew will be wearing black or similarly dark-coloured clothing in order to be fairly inconspicuous, so that they are not particularly distracting to the audience in the carrying out of their routines and tasks.