After completing his studies in graphic design at the Royal Academy of Fine Arts in The Hague and the Royal College of Art in London, Dumbar opened the now prolific Studio Dumbar. Though based in The Netherlands, Dumbar puts great emphasis on design that speaks across borders, with no less than 5 nationalities amongst his staff.

The company splits their jobs into two categories: Visual Branding, which holistically integrates anything from logo design, website interfaces and building layout; and Free Spirit, which allows designers to work without the restraints of a strategy. Their clients include Shanghai General Motors, Museum Valkof, Dutch Post, KPN, Randstad, and SSH Utrecht. Currently they're also busy developing the new corporate identity for the Dutch Government.