MAKING HOLOGRAMS OR HOW TO PRODUCE SECURITY HOLOGRAMS

The mass holograms production includes chain of processes. Some operations, like origination, electroforming and embossing are basics in holography. They differs holographic production from standard printing processes. Later follows the converting operations: adhesive coatings, slitting, rewinding, kiss-cutting. Depends of end product, manufactures use printing technics,  like hot stamping, laminating, numbering, personalization in the finish.

Origination

The first step is making the original hologram image, called Master hologram. The process needs special optical equipment, which records original image onto glass plate with photo-resist. After photo-resist developing, the result is Master hologram.

Different technics for mastering are known by different names: 2D/3D, Dot-Matrix, E-beam, Lidogram. In spite of the sophisticated result and security level, all types of Master holograms are a collection of microscopic peaks and valleys on the plate surface. The next goal in mass hologram production is to transfer this microscopic surface relief to metal tool, called Holographic shim and multiply the single image to mass quantities.

Embossing tools

The process of preparing tools for mass hologram production pass through the following steps:

- Converting Master hologram from photo-resist to nickel;
- Multiplying a single image from a nickel original to a plastic base (recombining);
- Converting multiple images from plastic to nickel. This product is called a Master shim;
- After that the Master shim is used as an original for the reproduction of Work shims using electroforming again.

Electroforming is the process of copying holographic images. Depend of task it maybe converting image from photo-resist or plastic to metal (nickel), or just metal-metal copying.

Recombining is the process also known as step and repeat, multiply the single image from Master hologram. The result is big size holographic plastic plate -in narrow web embossing up to 12"x12".

Electroforming and recombining complete prepress process for mass production of holograms. Work shims are used as instruments for embossing.

Embossing

Thin nickel replica is used to press surface pattern from Work shim into a plastic foil. This process is called hologram embossing. The embossed pattern in the foil is provided with a very thin reflective layer of aluminum or another metal, like gold or chromium, which transforms the transmission hologram into a reflection hologram. In spite of the thinness of the metal layer, such embossed reflection holograms are completely opaque. Semitransparent alternatives can be achieved by the application of high-refractive-index layer (ZnSe, TiO₂) as well as partially metalized layers, which render so-called semitransparent overlays or see-through holograms. 

Converting

After embossing, depending on the end product, embossed foil gets through some additional operations: laminating, die cutting, adhesive coating, slitting, rewinding. Holograms can be applied to a product as an adhesive label, hot-stamped onto an item, used as a thread or tape, or used as an over-laminate of a product.

Finishing

For high security applications security printers use different additional processes like numbering and selective demetalization, hot foil stamping, laminating,

 

 

MAKING HOLOGRAMS OR HOW TO PRODUCE SECURITY HOLOGRAMS