Thin-film interference (TFI) is a process that causes certain frequencies of incident light to be magnified (constructive interference) while other frequencies cancel (destructive interference) when light reflects off a membrane with an inner and outer layer. When the thickness of the membrane is just the right thinness, the process of TFI can turn white light into the colors of the rainbow.
TFI is the same phenomenon that causes color in soap bubbles and oil films. To view the phenomenon in the Pipevine it is handy for them to land with wings facing the sun.
source:)
Like many of the black swallowtails, the Pipevine Swallowtail has pretty orange spots. The orange color is caused by deposits of pigment. The Pipevine also glows a blue color when viewed in bright sunlight. This is not caused by pigment but rather by a process called Thin-Film Interference (TFI).
More:p
Basically one theory of light is that it is an electromagnetic wave. Just like under the right conditions sound waves can cancel each other out, light waves can also cancel each other out. Noise canceling earphones work by generating waves that cancel out noise. The physics term for this is destructive interference.
hor/more in punjabi
White light contains a broad spectrum of light waves. In other words each color has a differnt wave length and frequency. The speed of a wave equals the wave length times the number of waves per second (frequency). In a vacuum, all light waves move at the same velocity. Therefore as the wave length gets smaller, the frequency has to get higher.
A film is a reflective layer that has an inner and outer surface. If the distance between these layers is in the range of a wavelength of light then the conditions to cause TFI, i.e. wave cancellation or amplification, is ripe. Since reflected light has to travel into and out of the mebrane, it travels twice the distance of the membrane thickness. That is called 2d in the reference. If this distance is equal to one wavelenth (or an even number of wavelenths) then the waves will add together and be brighter. If this distance is exactly half a wavelength (or an even multiple of this) then the waves will cancel each other out.
Accidentally yani hadsati tor per I have some shots are example of TFI 
Share your TFI images too
Never let anyone burst your bubbles or dreams.
