The colours in the peacock tail
|[Note Guidelines] Photographer's Note|
|The colours in the eye feather|
The colours in the peacock tail are particularly beautiful because they are bright and iridescent. An iridescent colour is a colour that changes with the angle of view. The colours are not produced by pigments but by an optical effect called thin-film interference that takes place in the barbules.4 In technical terms, the peacock has ‘structural colours’.
In the eye pattern, the barbules appear bronze, blue, dark purple and green. Away from the eye region, the barbules are uniformly green. The colours in the eye feather can only be seen on the front surface of the feather because this is where the barbules are positioned. The back of the feather is uniformly brown because the barbs contain a brown pigment.
The eye pattern: The particular beauty of the eye pattern comes from the rounded shapes that have a high degree of resolution. The ‘pupil’ of the eye is formed by a dark purple cardioid and the ‘iris’ is formed by a blue ellipsoid. These shapes are located within a pointed bronze ellipsoid that is surrounded by one or two green fringes. A very important feature of the eye pattern is that it is a digital pattern which is formed by the combined effect of many thousands of individual barbules. Some patterns in nature are formed by natural growth mechanisms, as with the spiral shape of the nautilus shell. However, the eye pattern in the peacock tail requires the precise coordination of independent barbs and this cannot be achieved by a simple growth mechanism. Barbules on adjacent barbs coordinate perfectly with each other to produce the eye pattern.
Camera: Canon 1D Mk lll
Time of day: 19:23 p.m.
Date: 20th November 2007
Weather conditions: Clear
Lens: Canon 100-400mm L IS
Filter: Hoya 77mm UV
Shutter Speed: 1/320
Focal Length: 400mm
Support: Hand Held
Original File: Digital RAW
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