case of a field rotated 90 u00b0 here the opaque separation layers within particles 8 are perpendicular to the surface of document 1 so that one can see through security layer 2 from above and the information in printed layer 10 becomes recognizable the example according to fig5 involves a variation of somewhat more complicated construction in which certain information was applied to document 1 with inventive optically changeable material m fig5 shows a section through a printed letter in a greatly enlarged representation specifically background layer 18 for example a black or dark gray background is printed on the basic material of document 1 here thereabove is layer 4 that is produced of optically changeable material m in the area of the letters to represent information 3 and of further material 5 for example conventional printing ink 5 in edge areas material m again has particles 8 embedded in microcapsules 7 in binder 6 as shown in fig1 and 2 particles 8 consist here of a white half and a dark colored half the dark color of particles 8 corresponds precisely to the color of colored material 5 surrounding information 3 background layer 18 also has this color in the state shown in fig5 a viewer looking at document 1 from above will therefore no longer be able to recognize information 3 applied in layer 4 in surrounding material 5 by material m by applying a suitably electrically oriented field particles 8 can be rotated so that information 3 appears white on a dark background and in dark.