FAQs

Embossed holograms

Embossed holograms are the shiny holograms seen on credit cards and packaging. The original hologram is made into a metal copy. Duplicates of this are made and these are used to make millions of copies by embossing the pattern into soft aluminised plastic.

Embossed holography is by far the most common form of holography as the material can be produced quickly and cheaply in large quantities. Embossed holograms are the type found on credit cards. The subject may be animated (stereograms) a small model (the Visa Dove), flat art work 2D/3D or 2D/2D or a diffractive pattern (Diffractive Pixel Image).

The technique of embossed holography lends itself to mass-reproduction. A run of several million holograms is not uncommon.

Embossed holograms are mastered on a Photo-resist plate, a light sensitive material on which ridged patterns of holographic fringes are recorded. The plate is very easily damaged and must be handled in clean conditions with great care. The photo-resist plate is a piece of glass, specially coated to:

• a) Record the hologram.
• b) Prevent internal scattering of light on the plate via a special coating.

Once the hologram is recorded, this glass plate is coated with a very thin layer of pure silver in a vacuum coating chamber to make it conductive to electricity. A nickel "shim" is "grown" from the master hologram in a special electroforming tank. This first "grandmother" shim is a thick (1mm) piece of nickel.

Once grown, (approx. 24 hours after being placed in the tank), it is peeled from the photo-resist, destroying the original photo-resist hologram. Copies of this grandmother shim are grown to produce mothers and copies are grown off the mothers to make daughter shims. These are now production shims that are fixed to a heated roller on an embossing machine.

A thin aluminised plastic film passes through a set of rollers and the holographic image is transferred or embossed into the plastic. The resulting material can be used as hot stamping foil for foil blocking, or is adhesive backed and wax paper backed for pressure sensitive labels (stickers).

There are two formats for embossed holography:

• 1. Narrow web (6" – 12")
• 2. Wide web (24" - 48")

The narrow web embossing machine can emboss a 6"X6" area and the maximum size for a single image hologram is normally restricted to this size.

For wide web embossing there is an additional production stage whereby small shims, typically one inch square, are mechanically recombined into a large single pattern. It is not possible to create a large single image with this technique. It is used to make a "wallpaper" pattern that repeats seamlessly to form a continuous pattern. Embossed holography is by far the most common form of holography, as the material can be produced quickly and cheaply in large quantities. Examples in addition to credit cards would include confectionery packaging, toothpaste packaging and other security holograms. Typically, a small security hologram would be produced on a narrow web machine, while packaging material would be produced on a wide web machine. A higher quality material is achievable using narrow web embossing.