Snowflake: Vibrant Core
Can you do me a favour? I know I say it all the time, but please view this one large. I think you'll get a kick out of the colours. :)
Early this morning we had interesting snowflakes, many with large hexagon centers and a few with vibrant displays of colour. The temperatures were relatively close to the freezing point so I needed to work quickly to get the images I needed to focus-stack. After more than 60-70 frames the snowflakes would noticeably begin to "sweat" (here's an unedited center crop of this snowflake as it starts melting: donkom.ca/gplus/DKP_1641.jpg ). The flash from the camera is likely the culprit, so this image was made at twice the ISO I usually shoot at to cut the flash power in half.
The fascinating part is the crazy and colourful patterns in the center... if you think it's some kind of trick, I'll take that as a compliment. :) This colour is created by the phenomenon known as thin film interference - you can read a bit about it here: donkom.ca/gplus/optical-interference-pages.jpg
This colour is caused indirectly by a bubble in the ice. The bubble has extremely thin layers of ice on either side of it, thin enough to invoke the interference described in the above link. As the thickness of bubble varies, so too does the thickness of the related ice and this puts the interior-reflected light out of phase to a different degree - making different colours. The bubble thickness changes the colours that you see! Science!
Like the science stuff, or the photography techniques? Pick up a copy of Sky Crystals, you'll find 304 pages of all the good stuff! www.skycrystals.ca - and let me know what you think!