Household Iridescence - colours in mist from a humidifier by Tim Stone (images). ©Tim Stone, shown with permission.

"I took this picture while experimenting with strobing my decorative humidifier.  It creates a nicely homogeneous mist using ultrasonics.

The iridescent colours and corona ring come from individual droplets scattering the strobe light to form an angular diffraction pattern. When the droplets are similar sized - as here - their individual patterns are the same and we see the colours. Patterns from dissimilar particles overlap to produce white or at most rather pastel hues. Thus the best iridescence comes from clouds where droplets have all formed more or less at the same time and are still sufficiently 'young' that their size distribution has not evolved and broadened.

Find these conditions in pileus cloud, lenticular clouds, aircraft wakes, subliming frost and.. ..decorative humidifiers.


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