Butterflies have taken the colour black to an entirely new level. The scales that shingle this insect's dark wings are nearly on par with the blackest of black coatings made by humans - except they're only a fifth of the thickness.
Nature has developed the ability to produce a wide range of optical effects most notably in the butterfly wing. Here, the authors report on the analysis of the structures responsible for ultra-black coloration across different butterflies and combine this with modelling to identify the key characteristics