UF4...no post work but the frame. This looks so much better in the wider version I've posted at the link below
http://www.deviantart.com/deviation/40606421/
I agree that this is a soothing photo. It reminds me of experimenting with Bromine and Iodine gases in chemistry classess at school (a looooooooooong time ago!). I think that the smoothness of the interlace between the colours is this image's best feature.