Abstract: Compositions containing an organic pigment coated with metal oxides, wherein the pigment particles are provided with a tenacious, dense, highly crosslinked coating of silica and/or alumina which is fixed by polycondensation of a silicate and/or aluminate with the free hydroxyl groups of a layer that densely coats the surface of the pigment particles and which consists substantially of partially hydrolyzed compounds of elements of group 4A or 4B of the Periodic Table selected from the group consisting of chelates of formula ##STR1## wherein R is methyl, ethyl, methoxy or ethoxy, R.sup.1 is methyl or ethyl and X is halogen or C.sub.1 -C.sub.4 alkoxy, and M is Ti or Sn, and of esters of formulaQ(OR.sup.2).sub.4 (III),wherein Q is an element of group 4A or 4B of the Periodic Table and R.sup.2 is C.sub.1 -C.sub.4 alkyl.