Butterfly wing surface. Coloured atomic force micrograph (AFM) of the surface of a scale from the wing of a butterfly. The tiny holes in the scales diffract light, causing the colouration of the butterfly's wings. This specimen was from an orange tip butterfly (Anthocharis cardamines). Atomic force microscopy uses a thin probe to build up an image of a surface. The probe is moved over the surface, and is kept at a constant distance from it. The movements of the spring on which it is mounted as it adjusts to the surface are built up into a computer model. Magnification: x8500 at 6x6cm size.