How To Measure Matting For A Picture Frame. 6 steps for how to paint a picture frame mat. A frame’s dimensions refer to the size of its opening.
All of our frames are measured by the inside dimensions. As a general rule, your mat should always be 1.5 times as wide as your frame, or wider.
10×20 Mat Board 10 X 20 Picture Frame Matboard For Any
Borders (top and bottom =, sides =) enter: Borders (top and sides =, bottom larger) vertical.