archival adhesive for cyanotype?

[Gregg Kemp <gregg@roanokesound.com>]

Does anyone know of an adhesive that is safe to use (archival) with  
cyanotype on any specific paper combination?  The adhesive would be  
applied to the back of the print, in just a small area near the center  
of the paper, to "float" it off the surface of a matte.

In other words, is there a combination of paper and adhesive that is  
not likely to damage the cyanotype?  Or perhaps a paper of a very  
heavy weight?  Or a way to treat the back of a paper before applying  
an adhesive?  Would an acrylic medium be safe, if it worked?

Gregg