Depth Variance
Finishing techniques that create several distinct heights in a single impression allow for complex and realistic textures on packaging. In multi-level embossing, the dies are engraved with multiple steps or gradients rather than a single flat depth. This allows a single image to have elements that appear to sit at different distances from the viewer.
The effect is used to simulate three dimensional objects, such as the beveling on a logo or the texture of a fabric.
Tooling Complexity
Production of the dies requires advanced computer aided design and precision machining. Because the male and female parts must match perfectly across several different heights, the clearance between them must be calculated for every part of the design. Brass is the preferred material for these dies because it can hold the fine detail needed for the transitions between levels.
The cost of these tools is higher than standard single level dies.
Material Stretching
Success depends on the ability of the paperboard to stretch without tearing at the deepest points. Not all boards are suitable for this process, long fiber virgin pulps are generally required for their high tensile strength. If the board is too brittle, it will crack at the edges of the highest levels.
Careful control of the heat and pressure is necessary to mold the fibers into the complex shape of the die.
