stress

Fortunately not too much of the work related variety...

I received a copy of the new Field Music CD yesterday and happened to notice the colours that arise from stress induced birefringence as the case was sitting in front of the iMac while I was ripping the CD.

Of course, the light output from LCD monitors is linearly polarized, so with a single linear polarizer on your camera you can do the above. I imagine the residual stress is caused by uneven and rapid cooling of the plastic during injection molding.