A standard string section offers five independent groups: violins I, violins II, violas, cellos, and basses. Any of the instrumental groups may be divided, although this is not always advisable with the basses. When arranging music with a four-part harmonic texture (SATB), there are numerous doubling possibilities.
The orchestrator should rely on the natural dynamics found in various registers of the instruments for best balance and mixture (i.e., a viola can be placed above the violins in a texture where it has the prominent melodic content, and the result will be very effective and striking). A theme given to the cellos in their upper register will dominate the ensemble if the violins and violas are in middle or low registers. The string section is more forgiving of wide spaces between voices than are the wind sections, due to the rich overtone content of the string timbre.
Several segments of orchestral scores are included in the Excerpts in Score, illustrating exemplary string section scoring. Refer to: