>>Does anyone have any relative speed comparison between this 2 Dichromate. I
expose my gum prints with pot. for about 20 mins. I am wondering about how
much it can be faster with Ammonium. Just a rough estimate would be fine<<
Yes. if your are using a saturated solution the difference should be a
quarter of the exposure ie :- 5mins rather than 20 mins I hope this helps.
pete