Measure the height and width inside the seat on back side of frame (where A and B meet). Cut The posterboard to this size. This will be used for your matting.
2
Measure the height and width of your photo or art. Subtract 1/8" from those dimensions.
Locate the center of your posterboard, using a ruler draw a box to that size.
Draw a smaller box inside that box.
3
Using a utility knife, cut the smaller box out and discard.
Using a ruler and utility knife cut from the corners of the larger box inward at the angle shown.
Using a ruler to align the box line accurately, score the line with the ROUNDED edge (not the blade) of a butter knife or a scoring tool.
4
Carefully fold the matting at the scored lines and crease with pressure.
Fold in the opposite direction and crease again.
Fold again so that the drawn lines are now hidden inside the folds.
Apply clear tape to hold the folds in place.
Attach your photo or art, centered over opening, face down, so you see the photo or art through the opposite side.
Insert matted art or photo into frame and secure with applicable tabs or stays on frame.
