"Hinge mounting" is a method of mounting artwork by suspending it against the mat or backing with tabs of tape.
Sometimes, however, loose media like pastels or charcoal drawings cannot tolerate being placed in direct contact with the window mat, which means you cannot tape them to the mat. You must tape them to the backing. The best way to do this is by creating an S-hinge.
The S-hinge always involves using a mat blank, which will subsequently be backed by foam board. The mat blank must have slits cut into it, so begin by cutting narrow slits in the mat blank.
To find the location for the slits, turn the mat blank face down and place the artwork image side up on the back of it, positioning it where it will be when mounted when placed on the face. Mark some guide lines to indicate this position. Then lift away the artwork.
About an inch down from where the top edge of the artwork will be located and about two inches from where the left edge will be, cut a slit in the mat board using a box cutter or utility knife. Repeat for a second slit two inches from where the right edge of the artwork will be located.
Caution: Don't attempt to cut through the mat in one pass; instead, score the mat repeatedly, usually four to six times, to get clean edges on each slit. You will be feeding tape through these slits so make them wide enough to accommodate the tape.
Cut two tabs of mounting tape about four to six inches long and feed them through the slits. The tape should be adhesive side out as it hangs down the face of the mat. Adhere the tape to the back of the mat in the area above each slit.
On the face of the mat, pull the tape taut and tape it down with a second tab of tape to prevent curling. Position the artwork face up on the tape and press down to adhere.
The artwork is now mounted to the mat blank, which will now be backed by foam board to fill the frame and create stability.
Should you ever want to remove the artwork from the mat blank, simply reverse the hold of the adhesive where the tape is affixed to the back of the mat blank, and then, after the lifting the artwork away from the mat blank, reverse the hold of the adhesive from the back of the artwork.
The S-Hinge is the preferred method for mounting pastels and charcoal drawings but can be used on any original artwork that is to be mounted without coming into contact with the window mat.