I suppose the thing is the end result shouldn't sound like orchestrated piano music. Can anyone think of a piece for orchestra that sounds as such?
I find it interesting that Ravel wrote numerous works that are literally 'orchestrated piano music' but yet they don't sound like that to me at all, even when knowing the originals. Works that would might simply bandy colours around rather arbitrarily, or simply sound unidiomatic, but Ravel is neither of these things - there's a real unique logic to his use of orchestral timbre which creates all types of correspondences. His traffic in the other direction (orchestra to piano) is less successful, I feel.
I don't think Berlioz composed at the piano.
