Optical fiber ribbon having an optical fiber with a radiation curable internal coating and a radiation curable colored coating disposed to surround the internal coating, and a radiation curable matrix material surrounding one or more of the optical fibers to form a ribbon, in which: the colored coating has a degree of adhesion to the inner coating which is higher than the degree of adhesion to the matrix material; and the optical fiber in the optical fiber ribbon shows, upon aging of the ribbon for at least two weeks in water at 60° C., an increase in the attenuation of the transmitted signal at 1550 nm of less than 0.05 db/km with respect to the attenuation of the assembled optical fiber measured before aging.