The present invention relates to the field of magnetic machine readable oxidative drying suitable for intaglio printing of security documents. In particular, the invention relates to magnetic oxidative drying ink for intaglio printing on a substrate, said magnetic oxidative drying ink having a viscosity in the range of about 3 to about 60 Pa s at 40° C. and 1000 s−1 and comprising a) at least one oxidative drying varnish, b) a plurality of core-shell pigment particles comprising a magnetic core and an external layer made of silver and c) one or more stabilizers selected from benzotriazole compounds.