Step 7: Cutting the Matting

I’m going to describe how to do a double-mat. None of this is very complicated, and you should easily be able to adapt what I’m describing to single, or multiple matting jobs. The visual difference between a single mat and a double mat is huge. Double-matted works stand out as looking much more professional than just a single mat. I highly recommend you always use at least 2 mats. Don’t go overboard though. More is not always better. I’ve personally never used more than 3 mats.

In a double-matted work, the two mats are called the “back mat” and the “face mat.” As you may have guessed, the back mat is the matting that sits in back of the face mat. The back mat is the one that actually sits right on top of your artwork. The size of the window in the back mat is what will constrain how much of the artwork is actually visible.

Artistic convention suggests that you use a muted colour for the face mat, and a bolder colour for the back mat, since you’ll only see a small strip of it. The darker border of the back mat will serve to visually frame the artwork and separate it from the relatively muted colour of the face mat, of which much more will be visible. The face mat should be lighter than the colour of the frame itself, but this is really all totally subjective. You’ll settle on your own style and preferences.

This step is just math. Don’t worry, it’s pretty easy math. To start off, take the measurements of your mounting board. In this example, the inside dimensions of our frame are 18″ x 15.5″. Recall that our rabbet is 1/2″ wide on either side, so that adds 1 inch to both dimensions, meaning that the mounting board should be 19″ x 16.5″. Mine is actually a little bit smaller, because I left a small gap to allow easy fitting. When you’re doing this step, use the actual measurements of your mounting board, rather than the “theoretical” dimensions, since the frame may not be 100% perfectly square (being off by even a millimeter affects squareness).

At this point, I usually switch over to metric, as doing these kind of calculations in imperial is just masochistic. For this project, my mounting board was 476 mm (about 18 3/4 “) by 413 mm (about 16 1/4 “). The diploma that I’m framing is 8.5 ” x 11 “, which is 216 mm x 279 mm, respectively. At this point, I should point out that you can’t just cut a window in your matting to this size, because you’ll see the edges of the artwork. You need to make the window just barely smaller than the artwork being framed, so you can’t see the edges. I’ll subtract 2 mm off each edge for this allowance, reducing my window dimensions from 216 mm x 279 mm to 212 mm x 275 mm.

Note: The matting materials themselves are archival-quality and acid-free. They’ll actually be in contact with the work being framed, so if you’re concerned about preservation of the artwork, you should use cotton gloves any time you handle the matting.

Do the same thing for the matting you plan to use for the face mat.

As we calculated in the diagram above, we want a window that is 275 mm x 212 mm, and the matting itself is 476 mm x 413 mm. To figure out where to make your lines, you need to calculate how much empty space will be on each edge of the window. First, I’ll do the width, then the height.

To calculate where to mark your lines in the x-axis, take the total width (476 mm), subtract the width of the window (275 mm) and divide by 2.

(476 – 275) / 2 = 100.5

(413 – 212) / 2 = 100.5

Note that the result is exactly the same! 100.5 mm is the distance we went in when marking the left and right edges of the window. This is because we chose our measurements in the beginning such that the width of the matting surrounding the artwork would be constant (3.5 inches; go back to Step 1 to see, look at section “Decide on Sizing”).

The window in the face mat will be slighly bigger, so a little bit of the back mat will be visible. To determine the lines for the face mat, first decide how much “reveal” of the back mat you want. Typically, you’ll want between 1/8 to 1/4 of an inch of the back mat visible. Since we’re working in metric, I usually go with about a 4 mm reveal.

Take your measurements for the back mat and add 8 mm in each dimension (don’t forget, you’re adding a 4 mm reveal along each edge, for a total extra width of 8 mm in each dimension) and repeat the math I showed above.

Follow the instructions for your mat cutting kit to cut the actual windows. For my kit, it involves placing the mat face-down on the bed of the kit, lining up the line with the edge of the guide. There is a bit of a trick here. Be mindful of which way your blade is angled. You want the bevel on the mat to bevel outward, toward the front of the frame. For my kit, that means I need to orient the mat such that the center is to the right of the line I’m cutting. Always make sure you put one or two scrap pieces of mounting board underneath whatever you’re cutting, to keep the cutting blade from cutting your actual guide.

Turn the mat 90 degrees and repeat this for the remaining 3 edges of your window. If you meticulously go just a hair past each stop line, then when you’re done, the middle should drop right out of the mat and you should be left with a beautifully crisp, sharp beveled window.

At this point, I usually attach the back and face mats to each other to ensure that throughout the rest of the process, the window openings remain lined up. I take two 1-inch strips of double-sided, acid free tape (I use Scotch brand, which I bought in an arts and crafts store [Wallack’s again]) and stick them to the back mat on either side of the window opening, about halfway between the window and the edge of the mat.