Artificial fibres in polarised light

Shell artificial fibres photographed with cross-poalrised light and filter...Manfrotto.The assignment was for the petrochemical company Shell, to illustrate some new artificial fibers that they had developed. ..I was given a bunch of these thin fibers, in different colors. They looked completely uninteresting, and I sat looking at them. I played around, taping some into patterns, putting others on a lightbox to backlight them, tried raking light from a photographic spot — all kinds of approaches, and none seemed to be getting anywhere. ..I decided that I might have a chance of producing an interesting image if only I could light them against a black background. I thought about a sheet of glass suspended a distance over black velvet, and I thought about suspending them vertically with black velvet draped way behind. But then I remembered that I had recently been playing around with a sheet of polarizing material sandwiched between two clear plastic sheets. It looked simply like an oversized neutral density filter, but the secret to using it optically was to backlight it and then place a polarizing filter in front of the camera lens. The simplest way was to put it on a lightbox and shoot straight down. By rotating the lens polarizing filter, you could reach the angle at which the two polarizers crossed at 90º and everything went a deep purple-blue — almost black. Objects placed on it would still appear, so in theory it was a neat way of getting a very dark background without, so to speak, actually having a dark background...It got more interesting that that if you used the set-up to photograph certain plastics, because the stress patterns in the plastic would appear as interference bands — multi-colored stripes, basically, like a rainbow. Pushpins and cellophane, I remember, looked very good like this. Plus, they stood out bright and beautiful against the rich purplish blue...So I tried the technique with these artificial fibers. And to my surprise, the fibers also showed intense colored stress patterns in polarized light. It solved the problem, and I had a series of images of these strangely glowing bunches of fiber.