He then undertook a European study tour which lasted four years, visiting Germany and Italy.

During these studies he was particularly influenced by the art historians Wilhelm Vöge and Adolf Furtwängler.

Back in Norway he was appointed secretary of the Society for the Preservation of Ancient Norwegian Monuments.

While in this position Fett carried out a large documentary work on church art from the Middle Ages throughout the country.

After the death of his father in 1911, he took over as manager for the family company, including the factories Høyenhall Fabrikker.