1. Many
orchestras go through the trouble of making sure that bowings match within a
section, and, where applicable, across sections. Doing so sends a strong visual
message that everyone is working together, doing the same thing at the same
time. The sight here reinforces the sound. When sections don’t bow together, it
“looks bad.” However, some orchestras (most notable perhaps was the
Philadelphia Orchestra under Leopold Stokowski) favor the richness of sound
that comes with “free bowing.”
2. Bowing can create two interacting rhythmic streams. Sometimes the left-hand fingers move in the
same rhythm as the bow, creating a one-to-one ratio. Other times, there are
several different notes played under one bow, creating 2:1, 3:1, 4:1 ratios,
etc. In some cases, the duration of the note on the page is longer than can be
played in one bow stroke. Thus the bow changes will articulate different
rhythms than are written on the page. Very often, players are encouraged to
stagger bow changes to prevent projecting a real strong rhythmic articulation;
the effect is that of “free bowing” mentioned above. Listeners are expected to
overlook this and understand what they hear as one long sustained note.
3. Rhythm
and meter are often a consideration when choosing to play a note up-bow or
down-bow. Thus, bowing decisions are very often analytical decisions. Sometimes
bowing decisions are purely practical: it is easier (for me, at least) to
transition from an up-bow stroke to pizzicato because the up-bow gradually
brings my left hand closer to the fingerboard.