Goniophotometric reflection properties of interference-colored fiber with the alternating multilayer

The goniophotometric reflection properties of interference-colored fibers, based on the mechanism producing the brilliant tropical blue color of the wings of male Morpho Sulkowskyi, were compared with those of dyed fibers. When an incident light was applied parallel to the fiber axis, the shape of the goniophotometric reflection curve of the dyed fibers showed a broad distribution with the maximum quantity of reflected light occurring at nearly a specular angle. On the other hand, that of the interference-colored fibers showed an extremely sharp distribution with the maximum quantity of reflected light occurring at about a specular angle. In contrast, when an incident light was applied vertical to the fibers, both the dyed and interference-colored fibers showed broad distribution curves with the maximum quantity of reflected light occurring in a region larger than the specular angle. Based on these results, the contrast gloss of both types of fiber was estimated. Compared with the contrast gloss of the dyed fibers, that of the interference-colored fibers was extremely large. It is thought that this difference in contrast gloss might be mainly attributable to the alternating multilayer structure of the interference-colored fibers.