FrostWerks
Low Temperature Focus Stacking
These images show ice crystals that have formed on various objects, producing miniature works of art that are each unique and with an ephemeral beauty. The crystals are fragile, with their formation and shapes being very susceptible to their environmental conditions and the stability of those conditions (air temperature, moisture content, vapour pressure, radiant heat, rate of change etc). They exist for a fleeting moment of time and as conditions deteriorate, they melt away and their unique forms are gone forever.
Photographing ice crystals and frost formations at this macro scale and magnification involves a very narrow depth of field and technical issues associated with using camera equipment in freezing conditions for prolonged periods of time. The photographic technique involves focus stacking of multiple images (typically 80 minimum) to get each object completely in focus as seen at Strohtography.
The ice crystal and frost formations shown in the images are made up of a combination of different types, mostly hollow and solid rods crystals, dendrites, and ice spikes. Their individual and overall growth appears random and chaotic but are highly ordered as they are formed by very simple forces acting at the atomic and molecular levels.
The ice crystals grow by water molecules in the air attaching to oxygen atoms on a cold and suitable surface. The hollow and solid rod crystals typically grow from tiny hair-like stalks which form, grow, and then change during growth into hexagonal rod shapes and cup-like shapes. Ice spikes grow due to a different mechanism, described below.
Most of the images show ice crystals growing on frozen water drops that are between 4mm and 8mm diameter. As the water drops cool down and freeze, the different environmental conditions cause different ice crystals to grow with one common form being an ice-spike.
When a water drop is exposed to freezing night air, its outer surface in contact with the air cools down at a faster rate than the water contained within the water drop. The surface freezes over first, forming a skin of ice. The water inside this icy skin continues to cool down and expands as it does so. The cooling water within the drop pushes its way out through the last remaining hole in the freezing outer skin and as that water reaches the cold night air, its outer surface freezes to form a hollow spike. The cooling water within the water drop continues to expand and flows up the middle of the freezing spike extending it until all the water within the drop has frozen completely and the spike freezes solid.
A detailed look at the frozen water drop images shows patterns frozen into their surfaces. These look like cracks and dimples and are the precursors of another form of ice crystal growth. The cracks and dimples are where the freezing skin of the water drops have cracked and buckled due to the pressure of the expanding water within each drop before they freeze solid. From these cracks and dimples tiny plate-like ice crystals grow perpendicular to the surface features. When these flat plates are large enough, tiny hair-like stalks of ice start to grow perpendicular to them and the hexagonal hollow and solid rod-like crystals grow from the stalks. What initially appears to be a chaotic and random growth of ice crystals on a frozen water drop and other surface is actually a highly ordered structure dependent on the surface features the ice crystals grow from.
