Thank you sarah, there was an actual critique i read about this painting that said Dr. Tulp would have wanted the portrait to be painted in the way you described it with emphasis on him (the surgeon) and his audience of onlookers who paid money to be at the anatomy lesson. The fact that Dr. Tulp is wearing a hat as the others in the photo are not is also a symbol of his authority in this portrait. Rembrandt was considered revolutionary in the fact there isnt a background only a foreground in this group portrait.