Need Help

[ken]

Any ideals in how to get an old sign painted on paper and then glued to a cardboard backing. 15 by 40 inches. The problem is over time the cardboard is not flat anymore. There is no value here so is there a process or adhesive I can use to get this to laydown flat on say a piece of 12" foamboard?

 

[05]

Furniture restores faced with a warped cabinet or table top will sometimes cut grooves (either straight or v-shaped) along the length of the warp to relax it. You could try something similar.

Alternately, you could score the cardboard in a grid, and start to peel away layers of the cardboard until it is thin enough to relax. This is part of the process called 'backing removal', which my boss says is the scariest thing a paper conservator does.