This effect was generated in Filter Forge, a Photoshop plugin that allows you to create your own filters.
"Photo or Texture" offers 6 choices;
no.1 Image covered in oily substance
no.2 Image, oily and roughly distorted
no.3 Texture, a woody/painted feel
no.4 Texture, an oily/petrol rainbow surface
no.5 Image, distorted. This has several controls;
"no.5 How You Like" gives three options, 1-distortion, 2-oily surface distortion and 3-another distortion.
"no.5 opacychooser" gives rainbow petrol tints, from clean image to full rainbow colour.
"no.5.1 distortamount" affects only the first option of no.5 and changes the amount of distort.
no.6 Image distorted with offsets, and has it's own controls
Some notes for editing. I like this filter with a "simple filter" result too, it has a cleaner and lighter look. This one with the surface filter is darker and metallic, I like both.
Thanks to Crapadilla's noise lab and pattern lab forum threads.
oil oily petrol liquid rainbow fairy spectrum distort