PURPOSE: To provide security protective paper for bank notes or the like which are provided with a device for security consisting of strips or yarn having metallic stripes between the two sides of paper which are not capable of irritating or copying.

CONSTITUTION: The security protective yarn having a metallic layer partially free of the metallic layer indicating a pattern, design, indicia as a strong highlight to be background of the metal which is practicably undetectable with reflected light but is extremely darker than the paper adjacent to the yarn when viewed with transmitted light without the aid of a lens or another observing means is built into the paper. For example, the strips of a relatively broad width are built into the interior of the paper while fibers deposit. If dyes are used in the layer on one side of the strips or yarn for security or one of these effect objects is built into a plastic substrate for metal, the highlighted areas are colored when illuminated with the transmitted light.