On the best of days, cutting mats can be frustrating for a math-challenged person like me, and an hour of effort can easily turn into a pile of wasted materials. I wanted to see a new batch of matted photos today, but when everything kept going wrong, past experiences said to things away and wait for a better day.

Off-the-shelf mats rarely come in the sizes and shapes that I need, so cutting my own is a must. Museum board is expensive, though, and cutting the perfect mat requires patience, precise measurements and plenty of time. Running down a short checklist like this one usually helps me before I begin.

First, clean the work area and remove any clutter.

Collect the necessary tools in one place so you're not fumbling around for them while you're trying to work.

Put a new blade in your the cutter and make sure that the underlay mat is free of gouges that might catch the blade and flex it off course. Your lines need to be perfectly straight line from one side to the other.

Decide ahead of time which print or prints you will mat and write down the measurements. I use a pair of cropping L's to determine how much white space I need between the inside edge of the mat and the print.

I'm not a math wiz, so I use a mat cutting app on my phone. The measurements I use are down to a sixteenth of an inch. I use weighted mats, which makes the measuring a little more complicated, but the phone app takes care of that.

My mat cutter (a Keencut) has stops that I need to change for each cut, so I lightly mark the border widths / stop settings on the back of the board next to letters indicating the top, bottom and sides of the mat. This keeps me from having to look away from the precision cuts that I'm making.

If I make a good cut, the center drops out of the mat without leaving any noticeable overcut. If I have undercuts, the widow stays attached in a corner or two and I use an X-acto knife can cut this away. Lightly support the entire mat while you're doing this so the piece doesn't fall out and tear at the corner. If that happens, you'll have to start over and set that board aside, possibly to cut a larger size opening later.

It's frustrating when you do everything right and it still comes out wrong. That happened to me today, and it took several ruined mats before I realized I was miscounting the sixteenths of an inch markers on the mat cutter's scale. That's easy to do with the tiny scales in both metric and standard in three different places. Guess I should have made that second batch of coffee this morning.

Arrgh!

At last, a perfect cut! That's enough for today.