The final tip in this series of Tech Tips from Kluge about Hologram Stamping, outlines terms and phrases specific to specialty print finishing with holograms.
The complete hologram tip of the month series can be viewed or downloaded from the Kluge web site Users Guide to Hologram Stamping” at /hdownload.htm
Approval shim: Produced by the holographeur and sent to the customer for inspection and approval.
Color separation: The allocation of certain colors.
Embossing layer: The holographic structures are transferred into the embossing layer.
Half-tone: Immerging shades from light gray to deep black.
Hologram: An interference pattern, which shows the result of a reference light meeting diffused on an object and stored as such in a light-sensitive medium.
Image channel: Motives may be superimposed in the image plane (or the background) i.e. one image per channel. Only one motive is visible at a time, depending on the viewing angle. Thus there is an “image flip” where two motives are superimposed. A dynamic movement effect can be achieved, if a number of almost identical motives are superimposed.
Interference: The coherent superposition of two light waves where their in-phase amplitudes form a sum in each point. When there is interplay between two coherent waves (the same wavelength and phases) the amplitude increases or reduces. The result is an interference pattern/strips, which expresses the relative relationship of the phases of the two waves to each other.
Metallization: Metallization is an added metallic layer (usually aluminum) forming a mirror, which enhances the visibility of the hologram (thickness approx. 0.00003 mm).
Parallax: The difference between two different views of an object.
Plane/image plane: A 2-D/3-D-hologram consists of a number of planes, each of which contains piece of information. Linking these different planes produces a spatial effect. A foreground, mid-ground or/and background effect can be achieved depending on the positioning in the hologram. The main information, which is to be shown most strongly, is called the image plane.
Polyester carrier: The polyester film that acts as a carrier support for the lacquer layers in a hot stamp foil. It can also be the base film material in the self-adhesive label.
Pressure sensitive transfer adhesive tape: The pressure sensitive transfer adhesive tap is acrylic-based and fixes the self-adhesive label to the substrate. The transfer adhesive is on a liner (silicone paper). It has good resistance to UV and aging and is temperature resistant in the range -40 C to +120 C, for short periods even up to +180 C. (These values are averages, individual tests should always be made as adhesion to a substrate can be influenced by many factors.)
Prismatic: One of at least two intersecting planes in a given area, which cause changes to the direction and dispersion of light rays through diffraction. These areas give intense color changes of high brightness.
Protective lacquer (top layer): The top layer improves resistance to abrasion and liquids (i.e. solvent, juices, caustic solutions etc.).
Recombination: Reproduction of an image on the working shim (a single image or part of a continuous design). The large production shim necessary for the production process is created, this either contains a large number of single images distributed in a way which fits the reproduction machine or a large continuous area for continuous designs.
Release layer: In a hot stamp foil, this layer acts to release the polyester film after stamping.
Replication: Adding the holographic structure to a lacquer layer in an embossing machine using the production shim.
Sizing: Sizing ensures that the lacquer layers bond with the substrate (hot bonding layer). Sizing must bond firmly with the substrate during stamping and create a bond with the other foils, which make up the stamping layer.
Working shim: Nickel metalwork produced by the holographeur from which the actual production shims are created at KURZ by recombination and galvanic molding processes.
(Copyright LEONHARD KURZ GmbH & Co. KG 2003)