Do not add hinges to the sides or the bottom. The artwork needs to hang freely to allow for expansion or contraction from atmospheric conditions. Restriction may cause buckling or separation to occur. Set hinges in from the corner the width of the hinge. Do not attach hinges to an artwork's corners.
Corners tear easily under stress.
The artwork is laid face down on an acid-free blotter where the hinges will be applied. Attach near the corners along the top edge. Be sure the paste does not penetrate below where the hinge is attached. The artwork must remain free of the mat so it can be lifted. Do not rub wet hinges.