A holographic decal is used on driver's licenses, credit cards, passports and other documentation in an effort to make them more secure. Reflection holograms on mass-produced decals are visible in ordinary lighting, and are usually of lesser quality than a hologram with both transmission and reflection light waves. They are stamped on foil decals backed with a permanent adhesive. Many companies make them specifically using artwork their clients have provided.
Holograms are three-dimensional photographic images taken with the assistance of lasers, spreading the light to travel both through and reflect off the object. The resulting image retains the properties of the light in which it was photographed, appearing to the eye as a three-dimensional representation of the object. Holograms with both reflection and transmission light waves are deeper, sharper and of better quality than the reflection holograms found on decals. Light that reflects and interferes with each layer of the hologram is seen in different wavelengths on different angles, in different colors. This is called the Bragg effect.
The security holographic decal found on a credit card and other identification paperwork is typically of higher quality than a novelty hologram sticker. The adhesive used is strong enough so that the hologram cannot be removed without causing observable damage to the decal itself. These decals can be sold in rolls with sequential numbers on them, making it easy to identify an object stamped with one. A clear holographic detail can also be placed over a signature on an official document, both protecting and identifying it as authentic.
In addition to identification purposes, retailers who sell officially licensed merchandise or memorabilia can use a holographic decal to certify their inventory. They may advertise this fact so the buyer is aware that only the object containing this sticker is the genuine article. This ensures paper certificates are not forged and gives buyers proof of origin in case they decide to resell their items. Tamper-evident void release patterns can be applied to the adhesive so when the holographic decal is removed, the word “Void” is left behind.
Children’s pressure sensitive stickers sold in stationery supply stores and crafts retailers often contain holographic images or patterns. Fans of a particular cartoon character, sports team or supporters of a school may display a holographic decal featuring their favorite on their vehicle’s windshield or bumper. The licensee of the image will furnish it to the manufacturer for use in the hologram. These novelty stickers are usually of lesser quality than the ones made for security purposes.