Researchers have shown why intense, pure red colours in nature are mainly produced by pigments, instead of the structural colour that produces bright blue and green hues.
The researchers, from the University of Cambridge, used a numerical experiment to determine the limits of matt structural colour – a phenomenon which is responsible for some of the most intense colours in nature – and found that it extends only as far as blue and green in the visible spectrum. The results, published in PNAS, could be useful in the development of non-toxic paints or coatings with intense colour that never fades.
Structural colour, which is seen in some bird feathers, butterfly wings or insects, is not caused by pigments or dyes, but internal structure alone. The appearance of the colour, whether matt or iridescent, will depending on how the structures are arranged at the nanoscale.
Ordered, or crystalline, structures result in iridescent colours, which change when viewed from different angles. Disordered, or correlated, structures result in angle-independent matt colours, which look the same from any viewing angle. Since structural colour does not fade, these angle-independent matt colours would be highly useful for applications such as paints or coatings, where metallic effects are not wanted.
Continue reading at University of Cambridge.
Image via Pixabay/Will Zhang.