Where did Rembrandt learn to use lighting effects in his works ?
With the occasional help of assistants in Uylenburgh 's workshop , he painted numerous portrait commissions both small ( " Jacob de Gheyn III " ) and large ( " Portrait of the Shipbuilder Jan Rijcksen and his Wife " , 1633 , " Anatomy Lesson of Dr. Nicolaes Tulp " , 1632 ) .