Frost Kaleidoscope - Stunning colours!, page 1

The crystals grow across the glass from tiny nuclei and surface imperfections. Unlike fern frost these crystals are small and quickly jostle others before they can get larger. The growth nuclei were either very close together or conditions rendered crystal nucleation and growth was rapid.

Ice crystals on a window imaged by Jesper Grønne in Denmark.

Jesper used a 85mm f/1,2 lens and a reversed 50mm outside it to give an enlarged macro image. The image covers just a few millimetres.

How can frost produce these wonderful colours?

The secret of the magical colours is that he imaged the frost between two crossed polarising filters.

Ice is birefringent or double refracting. Placing a polarising filter each side of the crystals reveals the colours that result from interference between the two birefringent rays.

Colours are also produced by thin film interference. Distinguish between them by rotating the camera polariser. birefringent colours then change, those from thin films do not.

Source: OPOD 1 and OPOD 2

Remind me of these kaleidoscope tubes I used to play with when I was a child:

edit on 5-6-2012 by elevenaugust because: (no reason given)