Pigeon feather façades foil brand and currency forgery

SANTA ROSA, CA - Inspired by the colorfully pastoral imagery of abalone shells, butterfly wings, soap bubbles, mallard ducks, humming birds, peacocks and pigeons engineers in the Flex Products subsidiary of JDS Uniphase (San Jose, CA) are developing a dazzling array of interference-based pigment techniques for a range of applications that includes combating counterfeiting and painting cars.

Unlike chemically based colors, based on the selective absorption of specific wavelengths of light by organic compounds (chromophores), interference based colors depend on constructive and destructive interference in thin films such as abalone shells, butterfly wings and soap bubbles; or on the dispersion of light into discrete wavelengths by diffraction gratings such as the feathers of mallard ducks, humming birds, peacocks and pigeons. And since absorption based color is an intrinsic quality of the material being viewed, it does not change with viewing angle, while interference-based color, which can appear even in transparent and colorless materials, does change with viewing angle.

This can be a big deal for nations or corporations concerned with counterfeiting, because interference-based colors schemes incorporated into currencies or brand labeling cannot be reproduced through scanning or photocopying. Also unlike the engraved holograms on credit cards that shift appearance with viewer perspective, interference based color shifts cannot be copied by simply taking a wax mold. Even for purely commercial purposes such as painting cars or adorning any number of consumer items, interference based coloration methods essentially enable designers to work with a palette that is literally dynamic and sparkling.

The fact that color-shifting effects are obvious to the unaided eye makes them desirable for both decorative and security applications, and the benefit in security applications is twofold: the obvious color-shift helps to both detect and deter counterfeiting. That the color-shifting effects can only be reproduced through a highly sophisticated combination of technical and manufacturing wizardry, however, offers an additional advantage for security even though it can make the process a bit pricey for adorning commodity items.

Diffraction, thin-film, holographic, and organic color methods can also be combined, together and with other security techniques, to yield highly interesting visual effects as well as highly complex security patterns. For instance, thin film patterns color shift from long to short wavelengths with increasing viewing angle, while diffraction gratings shift color from short to long wavelengths. Diffraction gratings can also change and can also be rotated to yield different imagery. Perhaps because the resulting multi-dimensional color mazes convey color depth similar to the manner in which holograms convey spatial depth in two-dimensional space, engineers at JDSU refer to them as chromograms.

So far the thin film techniques in combination with various other holographic and coloring effects are already deployed on a variety of JDSU decorative and security products, while diffractive technologies are just completing development and beginning to enter the product mix. For security applications alone, the technology is currently in use on more than 100 monetary currencies worldwide, as well as in brand protection applications for wine and spirits, luxury goods, licensed products and pharmaceuticals. Counterfeiting of branded products, including software, pharmaceuticals, auto-aircraft spare parts and other consumer products, has been estimated to account for more than five percent of world trade and as much as US$500 billion in lost revenues annually.