Comparison of methods for colour shift effects

Plastic film Colour shift effect is produced in nature by different mechanisms including
pigments,light absorption and interference and by a mechanism called
photonice crystals.
In industrial applications various methods have been employed to reproduce
such effects.These methods reply on physical,chemical and mechanical principles.
This includes optical absorption,emission (LED),interference,micro-structuring
and scattering. In our recent work we have developed a colour shift effect on a
flexible film without the use of structural embossing,inks or pigments.