AMSTERDAM — With populist politicians across the Continent attacking the European Union and negotiations underway for Britain to leave the bloc, the very idea of a unified Europe seems to be under threat. Some artists feel the union needs to rethink its public image and refine its communications strategy to combat these attacks. In other words: to rebrand Europe.

The German photographer Wolfgang Tillmans has teamed up with a friend, the Dutch architect Rem Koolhaas, to encourage artists and other creative people to brainstorm ways for Europe to better present itself to the public.

They put out a call in March for rebranding proposals, asking: “How can the European Union be valued by its citizens and be recognized as a force for good, rather than as a faceless bureaucracy?” They requested ideas “for communicating the advantages of cooperation and friendship amongst people and nations.”

More than 400 proposals from 43 countries poured in. A German fashion designer had an idea for a unisex jacket that would serve as a ticket for public transportation in all 28 member states. A dance troupe with members from Albania, France and Italy proposed filming folk dances at European historical sites that could then be broadcast or viewed with virtual reality goggles. A musician from Hungary proposed a new anthem, and dozens of artists sent sketches for new European Union flags and designs for new euro bills and coins. Several proposals suggested the bloc needed to develop a new sense of humor.