The present invention relates to radically curable compositions, comprising (A) silver nanoplatelets, (B) one reactive diluent comprising 1 to 4 (meth)acrylate groups; (C) one, or more urethane (meth)acrylates (C), which are obtainable by reaction of the following components:



(a) at least one isocyanate having two isocyanate groups,
(b) at least one polyalkylene oxide polyether having at least 2 hydroxyl groups,
(c) at least one hydroxy-functional (meth)acrylate having one hydroxyl group and one (meth)acrylate group,
(d) at least one compound having at least one isocyanate reactive group and at least one acid function,
(e) if component (d) is present, optionally at least one basic compound which is present for neutralization or partial neutralization of the acid groups of component (d),
(f) optionally at least one monoalcohol having one hydroxy function, and
(g) optionally at least one compound having at least one primary and/or secondary amino group;
(D) one, or more photonitiators; printing inks containing the compositions and their use for the production security products. Coatings obtained after curing of the compositions, show one color, when observed in transmission and another color, when observed in reflection on both sides of the cured coating. The metal-like reflection of the coatings may be further enhanced by the presence of surfactants.