Today, holograms have been considered to be an effective way for protecting products and enhancing their authenticity. Holograms are used by almost all companies from the food, automotive and pharmaceutical industries to the manufacturers of spirits, documents, confectionery, audio and video products etc. We consider holograms as uncounterfeitable. However the truth of the matter is that there are still some ways to counterfeit holograms which are used in security. Commercial hologram designs can be counterfeited.

Counterfeiting Methods of Holograms

From the point of view of a counterfeiter, embossed holograms provides the path to easy money. There are certain straightforward ways to counterfeit such holograms which we give below:

• Holographic copying in one step: This is accomplished by simply contact copying the hologram.
  
  
• Holographic copying in two steps: Two-step copying is attained by illuminating the original hologram with a laser and recording the diffracted light in a second hologram. The second hologram is then illuminated to make a replica of the image in the original hologram, and the image is used to make a duplicate of the original hologram.
  
  
• Re-origination: This method involves creating a faithful imitation of the original artwork. For example, the Visa hologram is very straightforward to copy by re-origination. This is because the image is there on every card and any skilled sculptor can recreate as a solid model. Once a good model is made, it becomes easier for any holographer to make holograms and copies that will pass even a careful inspection.
  
  
• Mechanical copying: This is done by uncovering the embossed surface of the hologram and using it as a form to produce an electroplated copy, which can then be used to emboss counterfeit copies of the original hologram.

Each of the above method is very simple and there is no doubt that counterfeiters can easily produce a passable copy of any embossed hologram that exists today.

Counter Measures: How to prevent counterfeiting in holograms

Though there is no such proof that holograms can be counterfeited, it is always better to believe in the slogan "prevention is better than cure". Some researchers have come up with some effective measures to combat counterfeiting in holograms. These are as follows:

• Hidden Information or Complex Images: One method that can prevent counterfeiting is by including hidden information or by making the image so complicated that it is not worth to duplicate it, considering the time and money involved. Hidden information is of great value only if the cheater cannot find it or duplicate it. So, effective use of hidden information or any kind of complex images requires some sort of relatively simple and inexpensive reading device or decoding device.
  
  
• Variable Processing Parameters: This is one way which is extremely difficult to copy using either one-step or two-step copying. The method is to randomly change the exposure, development time or other processing parameters to produce variable shrinkage all over the hologram. This results into a hologram whose color varies from point to point. Because a laser is monochromatic, the brightness of a variable-shrinkage hologram changes dramatically with the shrinkage of the film. In fact, if the film is thick enough or the shrinkage is extreme enough, the copy in most of its regions will have no image at all.
  
  
• Variable Information: Holograms are not easy to counterfeit if they include variable information like serial numbers, encoded personal information or dates. It is possible to record variable information on holograms while applying holographic hot stamping foil to a substrate.
  
  
• Special Materials: Another method for complicating the optical copying process is to make the hologram of some special materials which alter the polarization of light or selectively scatter particular wavelengths of light or else the hologram can be over coated or laminated under such materials.
  
  
• Multiply-Connected Holograms: Another effective approach to preventing mechanical copying of holograms is to make the holograms multiply-connected which means that the hologram is composed of dots or else is punched full of holes.
  
  
• Combined Counter Measures: All the methods mentioned above may not be the perfect solutions for preventing counterfeiting. In such cases, combined countermeasures or countermeasures used in combination can be highly effective against all of the counterfeiting methods.

Conclusion

Important tip The "Ideal Hologram" will include variable information buried multiply connected hologram encoded information controlled variable thickness will be machine readable will NOT be "human readable" without using a reading device

There are many methods for counterfeiting security holograms. Though there is no indication whether these methods have been used by counterfeiters or not in the security field, the advancement of holographic technology and the high level of activity in the field will definitely lead to hologram counterfeiting. In the commercial sector, hologram counterfeiting have been occurring in recent years. Hence importance should be given in this area by adopting various methods to fight against counterfeiting on holograms.