Measure your artwork. You'll want to write down the
measurements on a piece of paper large enough to do a bit of math as
well.
Step 2.
This is the tricky part: the math. My image is 4" x
6.5" and my mat is 8" x 10".
First, decide if your mat will be horizontal or vertical.
In my example, it will be vertical.
To figure out the width of the sides of your mat, subtract
the width of your artwork from the width of your mat. Divide that number
by two.
Example:
8" – 4" = 4"
4" / 2 = 2"
Thus, each side of the mat should be 2" wide.
To figure out the top and bottom of the mat, first
subtract the height of your artwork from the height of your mat. Divide
that number by two. Your mat should always have a larger bottom than
top, so you want to subtract a bit from the top and add a bit to the
bottom. There is no hard and fast rule as to how much bigger the bottom
should be, so this will take a bit of practice to get a feel for it.
Example:
10" – 6.5" = 3.5"
3.5" / 2 = 1.75"
1.75" + .25" = 2" for the bottom
1.75" – 2.5" = 1.5" for the top
Just be sure to add the same number to the bottom that
you subtracted from the top.
Step 3.
The next step is to transfer your measurements to the
back of the mat. (The back! If you accidentally draw your lines on the
front, you'll get mad, and there will be swearing involved. I know from
experience.)
The tool I'm using in the above image is called a Matline and can be purchased at most art supply stores. It makes measuring your
window size much easier. Just stick your pencil in the correct hole for
your measurements, lineup the edge with the edge of your mat, and drag
it across. Repeat this for each side.
You can of course use a ruler as well. Just measure
the correct amount for each side a draw four lines to make a rectangle
for your window.
Step 5.
Check the window you drew against your actual artwork.
Please don't skip this step, or you may have another one of those swearing
incidents on your hands. Also, I like to mark the bottom with the name
of the artwork, just to make it easier to properly assemble the mat later.
