I have seen this done with water drops on a CD or DVD before but the colours are never as bright. My setup was to use my lightbox with a polarizer on top. I used a CD case cover and sprayed some water on it and sat it on top of the polarizer. On my lens I had another polarizer.
By adjusting the polarizer and turning the CD cover the effect changes. I took 30 minutes from start to finish including the collecting all the bit needed. Some had been left out on the dining room table already.
