A very knowledgable av fanatic on these forums told me this...
Seeing the rainbows is very much a state of mind (now thats not to say they aren't there) but try relaxing on your demo... a little yoga perhaps or a bottle of white. When you are stressed the rainbows are more prominent. When you are completely relaxed they seem to disappear. Try it!
Question. When i watch CGI movies I dont see one rainbow, not one. Why is this?
CH
PS. Pirates of the Carribean had quite a few rainbows all the way through so a couple of weeks later I had 2 bottles of white and low and behold I hardly saw any!! Mind you i didn't make it to the end of the film either