Instrumentation

Instrumentation is the study and practice of writing music for a musical instrument.

Writing for a specific instrument requires the ability to take into account the special properties of that instrument such as the following:

the pitch, timbre and dynamic range of the instrument and available tones in these ranges
application of chordss or other multiple tones
certain kinds of passages can be especially easy or difficult to play
playing techniques such as constraints of breathing, fingering, etc.
special effects, such as harmonics, clicks, pizzicato, glissandi and so on
notation conventions for the instrument.

See orchestration for a description of the difference between instrumentation, orchestration and arrangement.