Such patterns also occur in nature, where lattice like structures of similar dimensions overlap, are illuminated and move a little (such as waves of rippling corn). There are a host of man-made examples; such as the patterns created by overlapping fences, mesh or fabrics. Indeed, the term moiré is derived from a traditional type of silk which is washed and pressed together in layers, to give a pleasing washed out appearance of ripples.
There are countless examples of optical illusions created by this effect, and even examples in fine art (see below).
How does it work?
Whilst these patterns obey mathematical rules of some complexity, it is not necessary to design them from first mathematical principles; although some guidelines are valuable in creating effective patterns.
Firstly, the patterns can be random, but regular designs tend to produce symmetrical interference patterns.
Thin lines produce a more delicate effect than thick lines; but both are capable of producing the illusion of motion.
The space between lines determines the grain of the interference pattern.
Coloured lines generally follow Josef and Annie Albers’ theories of the interaction of colour; they can be passive, deceptive or unstable.
I want to create some interesting monochrome and polychromatic moiré patterns and see if I can project them holographically. Alternatively, I want to see if the hologram can generate moiré patterns – this is very experimental at the moment.
I think the next step will be to attempt to holograph a moiré pattern and see what happens. I should also like to experiment with combining holograms of holograms – how far can you go in reducing the process?