Bel canto singing is characterized by a focus on perfect evenness throughout the voice, skillful legato, a light upper register, tremendous agility and flexibility, and a certain lyric, "sweet" timbre. Operas of the style featured extensive and florid ornamentation, requiring much in the way of fast scales and cadenzas. Emphasizing technique over volume, bel canto style has famously been linked to an exercise said to demonstrate its epitome, where a singer holds a lit candle to her mouth and sings without causing the flame to flicker.
While the bel canto period is typically dated to the early 19th century, the term itself did not come to be commonly used in its current sense until the middle of the 19th century. It was at this time that composers such as Wagner began to call for larger, more dramatic voices; opponents of this trend complained, with Rossini, "Alas for us, we have lost our bel canto."
The sopranos Maria Callas and Joan Sutherland were probably the best-known bel canto singers of the postwar period. (Virginia Zeani and Leyla Gencer were both bel canto soprani of equal abilities, but they made fewer recordings and, thus, were less famous in America.) For many years, the bel canto tenor was a rarity; however, since the appearance of Chris Merritt and Rockwell Blake they have been making a comeback. Skilled bel canto tenors of today include Juan Diego Florez and William Matteuzzi.
References
"Bel Canto: A Theoretical and Practical Vocal Method". Mathilde Marchesi. Dover (1970) ISBN 0486223159
"Bel Canto". James A. Stark. University of Toronto Press (2003) ISBN 0802086144
The Twilight of Belcanto. Leonardo Ciampa. AuthorHouse; 2nd edition (2005) ISBN 1418459569
"Bel Canto: Principles and Practices". Cornelius L. Reid. Joseph Patelson Music House (1950) ISBN 0915282011