define the role of wardorbe standby in film and tv?

Answer 1

During lighting of the set, it may be necessary to have someone stand in the wardrobe to be used on the set to determine that the colors in the cloth, etc., are lighted properly. Someone has to present the wardrobe and move about the set under the lighting so the designer, director and tech can see what is going on.
Alternately, depending on the situation, a wardrobe mistress (someone from the wardrobe department) is kept on standby to repair or modify a costume so there is minimal delay in production.