Yesterday i tried to capture that nice rainbow-like optical effect, which sometimes can be seen in snowflake photos. This thin film optical interference effect also can be seen in soap bubbles.
In case of snowflakes, it can be seen rarely than in bubbles and usually it is more subtle, with pink and cyan colors dominance. Not any snowflake have thin enough layers of ice and air inside to produce this effect, and if we want to see and capture it, we need to choose right angle for camera, where light of snowflake's surface will reflect.
Don Komarechka described in detail this fascinating effect (among many other interesting topics about snowflakes) in his book
"Sky Crystals: Unraveling the Mysteries of Snowflakes".
For these shots, i pointed macro setup at snow crystals (tiny hexagonal plates) and changed angle of camera, hoping to see colors at camera screen. Lighting of scene was only dim gray light of cloudy sky. This is crops from unmodified shots, without any color or contrast enchancements:
