Mat Board Thickness Explained

Written by Mark Rogers

Imagine that today is your birthday, and your loved ones have taken you to an acclaimed steak restaurant. Looking over the menu, you see a porterhouse steak and a tenderloin steak. Which would you choose? My answer: Porterhouse all the way.

Why? Because a porterhouse steak is about 2 inches thick, whereas a tenderloin is only 1 to 1.5 inches thick. I figure, why not enjoy the best when I’m dining out, and especially on my birthday!

In the case of mat boards, thicker is also best, although for wildly different reasons than culinary bliss. Here are the primary virtues of a thicker mat board:

  • A sturdy, substantial surface keeps the mat from warping and damaging your artwork.
  • The thicker the mat, the greater the depth of field, aesthetic appeal, and professional polish.

First, Why Use a Mat Board?

As a quick refresher, mat board (also called frame mat, photo mat, or simply a “mat”) is the board that lies between your artwork and the glass or acrylic layer of your frame. It protects your art from resting directly against the glass, from being discolored by the acidic properties of a wood frame, and from external factors like humidity.

Artistically, a mat board serves as a border, acting as “white space” that draws the viewer’s eye into your photo or painting for stronger visual interest overall. To help make a secondary color in the image pop more, you can use a mat of similar color. Of course, there’s no law saying you must use a mat board in framing art, but we believe it’s a great idea and we strongly recommend it!

Ply = Thickness

When choosing a mat board, thickness is one of four main elements to consider. Thickness is measured in ply, which is not standardized like inches or millimeters, so every 4-ply mat board won’t be precisely the same exact thickness.

A 4-ply mat is about 1/16-inch thick while an 8-ply mat is about 1/8-inch thick. These are the most common, but 6-ply, 2-ply, and 12-ply are also available. You could also stack two 4-ply mats to get a similar effect of an 8-ply mat.

4-Ply vs. 8-Ply

Let’s compare and contrast the two most common mat board thicknesses:


Example: Frame Destination carries many 4-ply mat boards, including this conservation-quality Crescent Select 4-Ply Window Mat Board. Available in 56 colors from Cornflower to Cabernet (and five shades of white!), these boards are made of alpha-cellulose, meaning the surface, core, and backing are acid free and lignin-free.


  • Sturdy surface keeps mat from warping and damaging art
  • More depth for a more dramatic look
  • Comes in beautiful neutrals with solid color from core to surface

Example: Our Crescent 8-Ply RagMat Museum Mat is made of 100% cotton. Cotton mat boards are often called “rag,” which is the same term used when talking about the paper used for making money. Considered museum conservation quality, this mat is extremely durable and is available in several shades of white and cream, as well as black.

Back to the Sizzle

Returning to my steak example, there may be times when an 8-ply “porterhouse” mat isn’t necessary. If you want to save money, or if the piece you’re framing is only temporary (i.e. up to five years), then a “tenderloin” (4-ply) may suffice. Often the quality of the mat board itself comes into the decision. For detailed explanations about the types of mat boards — cotton rag, alpha-cellulose, and paper — including notes on acidity and color, see this helpful infographic.

Head to our website, where our extensive menu of mat boards is guaranteed to satisfy your appetite. Sorry, couldn’t resist.

Happy framing!

Last Updated February 9, 2023