How do I use Iridescence?
Iridescence is directly correlated to your shininess map. To use it, apply a shininess map and enable the Iridescence toggle from the Inspector.
Examples of this phenomenon would be bubbles, oil slicks, fish scales, etc.
How Much Is Too Much?
If you put a fully white texture as your shininess map, everything will be a harsh rainbow, and you will not be able to control the intensity easily. Conversely, if the whole texture is black, nothing will be iridescent, no matter what you do.
We suggest using greyscale values in your shininess maps, and controlling how intense they are with the “Iridescence” Slider from the “Inspector” Tab.
Here is an example of what a material can look like with some iridescence