What size mat do I need for a frame?

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As an emerging artist, someone who is in the process of making art their business, I receive inquiries about about the size mat needed for a frame. Since I mat and frame a lot of my art, I wanted to explain how I go about it. There is always the option to take my work to a frame shop, but doing it myself isn’t that hard.

If you want a piece of art framed, a work on paper, you need a mat. Works on paper are usually framed behind glass with a mat. If you go to a frame shop, they will help you figure out everything you need. They will help you select mat colors and frame styles.

But if you have a good idea what you want, you can do it yourself, purchase the mat and frame in a store or online. To do so it is helpful to learn a little about what all is involved.

What size mat  do I need for a frame?

A sheet of cardboard (mat board) placed on the back of a picture, either as a mount or to form a border.

Oxford Dictionary

Why I learned how to cut mats.

I learned how to cut mats when I attended community college. Every piece of art that I created had to be critiqued in class. In ordered to be critiqued it was required that the artwork to be in a 2-inch black mat. We also needed to put black electrical tape around the edges. That was standard for portfolio work at that time.

I learned to cut my mats on a large in need of repair mat cutter and I sometimes cut them by hand with a carpet knife, sans the beveled edge. Cutting mats requires some thought and calculation in order to create them successfully.

What I think about before I start to create.

Actually, when I begin to paint a watercolors or any other form of art that is created on paper, the first thing do is figure out what size my art work needs to be. I usually think in terms of a standard frame size, and how large of a mat I want. The lessons I learned in community college I use every time I start a new watercolor painting.

Just the other day I brought a sheet of 300 lb Arches cold press watercolor paper. Probably the most beautiful piece of paper in the world, or at least I think so. And I spent about 15 minutes deciding what I wanted to do with it. I have a definite painting in mind. I knew I wanted to it to be on the larger size piece of paper, and I had a frame that I wanted it to fit into.

With all that in mind, I had to figure out how to cut the watercolor paper. It is 22 by 30 inches. I really wanted a 16 x 20 piece of watercolor paper, but instead I cut it 15 x 19-inches. That way I could get two paintings of the same size, out of the one sheet of watercolor paper. That makes more sense. I will make up for the inch that I lost while cutting the paper by increasing the width of the mat and using the frame I have.

Helping my collectors figure it out.

The same week I sold a small print to young man. It was a gift for his wife. He wanted to add it to an art wall in their apartment. He purchased the print after I spent some time explaining about what mat size he needed. I realize that this is something that people don’t easily understand. Even though I cut mats all the time, I also know when I’m cutting them, I sketch out a diagram and check and double check my math. Bob Villa on the show This Old House always said, “measure twice, cut once”. That is good advice for cutting mats too.

How to figure out what size mat you need.

There are several things you must take into consideration when calculating mat sizes; the artwork, the mat, and the frame.

For original art, the artwork is a fixed size. Frame size is a choice you can play with and even order a custom size. Mats are even more flexible in the decision-making process.

If you are ordering a print, then you have choices in your artwork size.

If you are starting with a frame, maybe it is one you have and love and you want a new piece of artwork it so you are planning to purchase more art. You will want to know what size of art or print to buy. You also need to decide if you want to mat it.

There are lot of variables here. Just start with what is fixed.

An example:

I have just finished my 15 x 19 painting and I want to submit it to a show. They will ask me for the finished size when I fill in the paperwork or online form. I already have an 18 x 24 frame. All I have to do is figure out the mat size I need to cut. I do this before I submit to the show to make sure it works. I like to use mats that are between 2 and 4-inches. Will that work for me?

I must take into account that I need some overlap of the mat and artwork. At least a half inch on each side is a good amount. I decided on an inside cut for the mat of 12 x 18-inches. Next, I subtract that from 18 x 24-inches. There is a 6-inch difference. I divide that by 2. That means I cut a 3-inch mat. See diagrams below.

What size mat  do I need for a frame?
What size mat  do I need for a frame?

Another example.

My buyer wanted a 6 X 6-inch print with a 1-inch mat. That made the final piece 8 x 8-inches. When he looked for a frame, he needed an 8 x 8-inch frame opening. You have to disregard the outside size of the frame, the important measurement is the frame opening. Knowing your mat size will help you purchase the right size frame.

The 6 x 6-inch print with a .25-inch border
The 6 x 6-inch print with a .25-inch border. A transparent mat shows you the overlap you need. The mat is 1.25-inches around with a 5.5-inch opening.
What the finished matted piece looks like.
The outside of the mat is 8 x 8-inhces.
You will need a frame with an 8 x 8-inch opening.
The finished framed piece.
The outer edge is 8.5 x 8.5-inches. This is the measurement needed to understand how much wall space is used.
The frame is transparent so you can see
the overlap of the mat and frame.

How to cut a mat.

You may not want to cut your own mat, but if I walk you through the process, I think it will help you understand the how it all works.

I am getting ready to photograph a series of watercolor paintings and I want to put them in a frame with a mat to take the photos. I have the frame. It is 18 x 24-inches. The paintings are 15 x 19-inches.

This is my process.

  1. Measure and cut two pieces of mat board 18 x 24-inches. One is for the mat, the other is for the backing. I use a T-square ruler and a carpet knife. I cut it on a fabric cutting mat. The leather gloves are to protect my fingers because I have cut myself and was in need of stitches. Be careful!
What size mat  do I need for a frame?
Cut mat board
What size mat  do I need for a frame?
Measure art work
  1. Figure out the difference between the painting size and the frame with an overlap. I ended up deciding on a 3-inch mat and had more than the 1-inch overlap in the height. 18 x 24 minus a 3-inch mat creates an 12 x 18 mat opening. (See diagram above.)
  2. A mat corner markers is used to mark the back of the board at 3-inches. I used a ruler to connect the marks.
Mark the corners on the back
Connect the marks

  1. The mat cutter is set for a 3-inch mat to cut the inside edges.
  2. Always check the finished mat to make sure it works.
Mat cutter
Check the mat

Now I am ready for my photo shoot.

Biz News


To celebrate 1000 followers on Instagram I am giving away four small matted prints that I love! The Giveaway ends Saturday, May 29th at noon. I will announce the four winners first in my newsletter and then at noon Sunday online.

In order to enter the drawing you must:
1. Follow me on Instagram. @ruthieonart2
2. Like the post. (the Giveaway information is in)
3. Save the Post
4. Put the Post in your Instagram Stories and tag me. If your account is private take a screen shot and DM me.

Then for Bonus entries tag one person who you think would be interested in the Giveaway. And for 3 extra entries sign-up for my newsletter list. See the form at the upper right corner of this page.

Thanks you and as always Be inspired!

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