 Complete the following phrase:  The two worked together at G. Eifrigs Københavns Lervarefabrik in Valby in 1885 before joining Bing  Grøndahls porcelain factory the following year. Thanks to the firms artistic director Pietro Krohn, who had been their instructor at the Arts and Crafts School, they were given a studio of their own where they decorated the Heron Set, pioneering the firms underglaze technique. The set was successfully exhibited at Copenhagens 