Ultraviolet photography Silicon (from which DSLR sensors are made) can respond to wavelengths between 1100-190 nm. Photography based on visible fluorescence induced by UV radiation uses the same ultraviolet illumination as in reflected UV photography. However, the glass barrier filter used on the lens must now absorb or block all ultraviolet and infrared light and must permit only the "visible" radiation to pass. Visible fluorescence is produced in a suitable subject when the shorter, higher energy ultraviolet wavelengths are absorbed, lose some energy and are emitted as longer, lower energy visible wavelengths. UV induced visible fluorescence photography must take place in a
Ultraviolet communication in butterflies UV reflecting scales are composed of raised longitudinal ridges and perpendicular cross ribs that connect the parallel running ridges, forming a grid. The ridges possess lamellae that run on top of and parallel to the ridges and microribs on its sides. The partial overlap of lamellae structures causes thin layer interference resulting in the reflection of light with a wavelength within the ultraviolet spectrum. The other ultraviolet signal in butterflies, absorbance, was determined to be governed by pigments called pterins. In wings containing this pigment, the wings are unable to reflect ultraviolet light as well as without the pigment because