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Color and Light · entry 48 of 52
Butterfly wings often shimmer with structural color produced by tiny scales instead of dyes.
The longer version
Each wing is covered in overlapping scales, and each scale carries ridges and cross ribs spaced hundreds of nanometres apart. Those ridges scatter and interfere with reflected light, so particular wavelengths are reinforced and the wing shines with a colour no dye produced. Removing the scales leaves a dull, translucent membrane.
Many species combine this with pigment underneath, using the structure to intensify a hue or to produce different colours from the top and the underside. Electron microscopy in the twentieth century revealed the ridge patterns behind the effect. Fossil specimens preserve the structures well enough for their original colours to be reconstructed.
Where this entry sits
These facts explore how light behaves and how human eyes turn it into the colors we see. Along the way you meet rainbows, prisms, mirrors, shadows, lasers, and optical tricks that fool our vision every day. The full list sits on the Color and Light page, where every entry is listed in order.
More From Color and Light
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Read 52Stop signals are usually red because the color stands out against most natural backgrounds.
Read 1The human eye detects color using three types of cone cells sensitive to red, green, and blue light.
Read 2Rainbows form when sunlight bends and reflects inside countless tiny water droplets in the air.
Read 3A prism splits white light into a spectrum because each wavelength bends by a different amount.
Read 4Shadows appear when an opaque object blocks light from reaching a surface behind it.
Read