During The High Security Printing Conference in Budapest we have presented our Novel Non-Rainbow OVDs Based on Diffraction Optics
Sub-wavelength structures are especially of interest. They produce optical effects that are not common for classical OVDs thus can be used as an effective visual security features:
- pastel colors;
- antireflection (black color);
- zero-order color shift;
- polarization contrast.
These first line inspection features are easily recognized by common people and are difficult to simulate for other widely used technology.