This isn’t a special ink of somethings just the chrome card, but with few colors spotlights hitting it and giving this rather special effect. However I might want to look into those special flip flop inks that really changes colors in certain angles. I know they are rather very expensive and an a1 sheet cost about 9 euro with those ink on it while a normal 300 gram with a certain color cost 1 or 1,50 euro.
