The marine painter Hendrik Dubbels is full of surprises. His oeuvre, published in Ulrike Middendorf's 1989 doctoral dissertation, displays such a diversity of style that Middendorf came to the plausible con- clusion that in addition to pursuing an independent career Dubbels worked with such marine artists as Simon de Vlieger, Willem van de Velde, Jan van de Cappelle, Ludolf Bakhuizen and Abraham Storck. These collaborations appear to have been dictated by financial need rather than artistic subservience, for on several occasions Dubbels found himself seriously short of cash.
Unfortunately, our knowledge of daily practice in seventeenth-century artists' studios is still rather scant. Painters belonged to the Guild of St Luke, which had strict regulations governing the profession. There were few if any art academies in the modern sense, and pupils trained with a master-painter. They gene- rally entered his studio around the age of 14, where they were initiated in the rules of art. They had to pay tuition fees, and the guild stipulated that the master had to give them a sound training and not just use them as errand boys. The advantage here, of course, was that a sound training ensured that the apprenti- ces produced good work, which upheld the reputation of the profession. A master was not usually allo- wed to have more than two apprentices at any one time, but occasionally this rule was waived in return for a contribution to the guild funds. After two years, providing a pupil showed talent, he could be pro- moted to assistant. When an assistant was sufficiently advanced he could submit his "master's piece" to the guild. Only recognised masters had the right to sign their works and set up a studio of their own.