Iridescence Definition - What is it?

Iridescence results in hue changes influenced by both the angle of observation and illumination angle.

By attenuating or amplifying certain frequencies, the interference of the reflections modulates the incidental light created by this optical phenomenon that results in multiple reflections from multiple semi-transparent surfaces.

The material thickness and amount of layers will change the interference pattern.

Where is Iridescence Found?

Iridescence can even be seen on thin soap bubbles and oil films.  The wavelength of the color will usually be narrow comprising of two to three different colors that change as the viewing angle changes. 

Iridescence can be found in animals, glass (like bongs), plants, and many other subjects formed by structures made in natural cells.  This type of iridescence is typically formed by the different surface gratings found on plant or animal cells in muscles or specialized abdominal scales.

Diffraction also creates iridescences in items such as prisms, DVDs, CDs, or clouds. This type of diffraction will create colors that span the entire rainbow of the color spectrum.

Spotting Iridescence

The human eye cannot see some iridescence, and specific structures prevent iridescence altogether. The structure of iridescent objects can also be altered by sometimes simple means. For example, a peacock dipped in water will lose its iridescence until it is dried.