Iridescence (also known as goniochromism) is the phenomenon of certain surfaces that appear to change colour as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, butterfly wings and sea shells, as well as certain minerals. It is often created by structural coloration (microstructures that interfere with light).
The word iridescence is derived in part from the Greek word ἶρις îris (gen. ἴριδος íridos), meaning rainbow, and is combined with the Latin suffix -escent, meaning “having a tendency toward.” Iris in turn derives from the goddess Iris of Greek mythology, who is the personification of the rainbow and acted as a messenger of the gods. Goniochromism is derived from the Greek words gonia, meaning “angle”, and chroma, meaning “colour”.
Nacre also known as mother of pearl, is an organic-inorganic composite material produced by some molluscs as an inner shell layer; it also makes up the outer coating of pearls. It is strong, resilient, and iridescent.
Sea shells are formed by the process of bio-mineralization where living organisms produce inorganic solids. Sea shells are the protective layers of marine animals called molluscs and other sea animals.
The colour that a sea shell has is not just to make the shell look pretty. It often acts as a camouflage, hiding these small animals from the predators that hunt them. The different shell colouring and patterns is even a means by which different species communicate with each other. Impurities like metabolic waste products that are present when the shell is being formed, gives the shell a different colour. Even what these little animals eat affect the colour of their shells. The food that the mollusc eats causes the little animal to produce pigments in the mantle of the epithelium of the mollusc. If the pigment is secreted continuously it creates a spiral or radial band but if it is periodic the shell develops sports or flecks.
Shells that are red in colour usually have carotene or pterodines in them. Brown and black hues are found in shells that have melanin in them. Some shell fish can even change their colour to hide on the seabed when predators are near.
Guess what! Another rainy day, cos we haven’t had enough of those 🙄. Have spent my day doing housework, and then processed all my shots from the WW1 vehicle and Steam Fair at Beamish, will post those soon 🙂 And my shot for the day is my little bottle of treasure, washed up in a shell on a beach. (Not really, it lives in my bathroom 🙂 )
Well that’s January over, and the end of the still life section of the 366, though I guess there may be some in amongst the other themes. I have really enjoyed this month, looking back at the beginning the first few shots were not very interesting, and not that well composed either. After day 5 I seemed to make a leap forward when I started trying to tell a story with the items I was choosing, and then also found out to do the simplest of shots like the flowers in the vases on a windowsill. I feel my composition skills have improved and hope that will help the rest of the project & my photography in general.
Tomorrow begins the black & white theme. A little bit of trepidation as I love colour best, so now to focus on shapes and textures and contrasts!
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