Preparation and adaptation of a musical work so that it can be performed by an orchestra.
Orchestration is a practice that requires certain qualities that not all composers necessarily possess. Indeed, one of the orchestral works that have traditionally been regarded as examples of brilliant orchestration is Maurice Ravel’s orchestral version of the piece Pictures from an exhibition by Modest Mussorgsky.
In commercial music, especially incidental music and soundtracks, independent orchestrators are often used to complete the work of the composer, to streamline the composition process and to meet the strict deadlines required by the audiovisual industry. The film music orchestrator works quite a bit on short pieces written by various authors.
Opera and Musical Theater
In musical theater, the composer typically writes a piano / vocal score and then hires an arranger or orchestrator to create the instrumental score for the pit orchestra to play. Broadway orchestrators work extensively on pieces written for piano or on a score that contains the script for the composition.