So was the subject in contact with the paper, or is there a lens somewhere?
I've been looking for a way to keep the weird colours of printed-out developing paper, and fixing always got rid of them. Did you expose for a long time?
BTW, welcome to APUG, and thanks for a very interesting picture!
Yes, the subject was sandwiched between paper and glass. No lens. Cannot remember how long I left this one out but usually I expose them for a few hours in the sun.
The colours change in the fixbath but some papers give extraordinary colours!
Thanks for your comment!