Page "Orchestration" Paragraph 8

Most orchestrators often work from a draft ( sketch ), or short score, that is, a score written on limited number of independent musical staves.

Some orchestrators, particularly those writing for the opera or music theatres, prefer to work from a piano vocal score up, since it is required to start rehearsing a piece long before the whole is fully completed.

That was, for instance, method of composition of Jules Massenet.

In other instances simple cooperation between various creators are utilized, as does Jonathan Tunick when he orchestrates Stephen Sondheim's songs, or orchestrating from a lead sheet.

In the latter case, arranging as well as orchestration will be involved.