Security elements and method for their manufacture

A security element, comprising:

• a) a substrate;
• b) a volume hologram formed in a refractive index modulated layer, which is obtained by holographically exposing a recording material to actinic radiation and thereon;
• and
• c) an embossed surface relief microstructure on at least a portion of the refractive index modulated layer,
• wherein the embossed surface relief microstructure comprises:
• platelet shaped transition metal particles, wherein the transition metal is Ag and/or Cu;
• and
• a binder,
• wherein the pigment to binder ratio is from 4:1 to 1:1000,
• the security element exhibits a gold color in reflection when viewed from the side of the embossed surface relief microstructure,
• a green color in reflection viewing the volume hologram from the unembossed reverse side, and
• a blue color in transmission, and
• wherein
• when the platelet shaped transition metal particles have a diameter from 15-40 nm and a height of 8-20 nm, the security element shows an angle dependent color change upon viewing from orange to blue,
• when the platelet shaped transition metal particles have a diameter from 30-70 nm and a height of 8-20 nm, the security element shows an angle dependent color change upon viewing from red to green, and
• when the platelet shaped transition metal particles have a diameter from 5-120 nm and a height of 7-17 nm, the security element shows an angle dependent color change upon viewing from blue to gold.