Printing gum on top of acrylic paint

Has anyone ever tried to print gum bichromate on top of acrylic paint? I'm trying a new project and so far it will not stick to the surface of the paint. I then tried a coat of gloss polyurethane spray on top of the paint, then the gum layer. It just kind of beads up and won't spread out onto the surface. I thought I'd then try a coat of PVA size on top of the poly/paint surface. It just beads up like the gum mixture. I got the idea of gloss polyurethane from Christopher James' excellent alt process book. Doesn't work for me (at least not the way I'm doing it). Any ideas for printing gum on this unusual alternative surface?
Thanks,
Steve
www.scdowellphoto.com

How about a thin coating of matt lacquer. Failing that, perhaps a layer of gelatin size would provide a suitable surface.