Dry mounting FB prints

[Fourtoes]

Its been a while since I last dry mounted any work. I recently mounted some whole plate FB contact prints onto foamboard with a dry mounting press, all nice and smooth but they seem to have curled/warped as if tighter on the print side? I cant remember this happening before..... any suggestions?

Thanks in advance.

[Sal Santamaura]

...I recently mounted some whole plate FB contact prints onto foamboard with a dry mounting press, all nice and smooth but they seem to have curled/warped as if tighter on the print side?...any suggestions?...

Yes - mount your prints to 100% cotton mat board, not foam core board. Then, when they come out of the dry mount press, place them under a heavy weight (e.g. a pile of books) until cool.

Foam core board is questionable even as an archival backing board, given that the EPS core can outgass.

[Harold_4074]

The relative merits of foamcore aside, the warping issue is most likely due to shrinkage of the printing paper caused by moisture removal. This is always a possible issue with dry mounting, and the conventional answer (particularly if the print will be experiencing large swings in relative humidity while unrestrained by a frame) is to dry-mount a second sheet of processed paper (scrap or otherwise) onto the back of the board. This tends to equalize the stresses which cause warping, even if both sheets expand and contract differently from the board.