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Print Frame Co 3 min read

The Complete Guide to Mat Board for Framed Prints

When to mat, mat width by print size, weighted bottom mats, color choices, single vs double, acid-free vs standard. Everything that matters.

Conservation mat board samples and framing tools on a worktable

Mat board is the part of a frame most people don't notice — until they see a print with the wrong mat, and then they can't unsee it. The mat does more than fill space between the print and the frame. It controls the eye's path to the artwork, protects the print from glass damage, and signals whether a print is decoration or proper wall art.

What mat board actually does

Mat board (also called mount or matte board) is a thick paper or card border that sits inside the frame, around the print. It has three jobs:

  1. Visual breathing room — separates the print from the frame so the eye reads the artwork first, not the frame.
  2. Physical protection — keeps the print from touching the glass. Direct contact with glass causes prints to stick over time, especially in humid rooms or bathrooms.
  3. Hierarchy signal — a print with a generous mat reads as gallery art; a print without a mat reads as a poster.

When to use a mat

Default: always use a mat. There are only three situations where you'd skip one.

  • Edge-to-edge designs — type-led prints, posters, full-bleed photography where the image fills the entire frame is part of the design intent.
  • Wall of small prints — for clusters of 4×6 or 5×7 photos in a tight grid, mats can fragment the wall visually. No mat keeps the cluster reading as one piece.
  • Frames smaller than 5×7 — physically there's no room for a meaningful mat.

Otherwise, mat.

How wide should the mat be?

This is the most common question and the most under-answered. Generic advice ("about 2 inches") ignores the relationship between mat width, print size, and frame proportions. The right answer depends on the print size.

Print size Frame size Mat width (all sides)
5×7 8×10 1.5 inches
8×10 11×14 1.5–2 inches
11×14 16×20 2.5 inches
16×20 20×24 2 inches
18×24 24×30 3 inches

This scales the mat proportionally with the print. The print always reads as the focus. We cut every size to order — 5x7 mats, 8x10 mats, 11x14 mats and 13x19 mats, including an 11x14 mat for an 8x10 photo.

The weighted bottom mat (advanced)

For portraits, fine art prints, and gallery-style framing, professional framers use a weighted bottom mat — the bottom margin is slightly wider than the top and sides. This compensates for an optical illusion: a print with equal margins looks bottom-heavy to the eye because the visual center of any rectangle sits slightly above the geometric center.

Typical weighted bottom: top and sides equal, bottom 20% wider. So if top, left and right are 2 inches, bottom is 2.5 inches.

Use weighted bottoms for hero pieces, single statement prints, and anything portrait-orientation. Skip for landscapes and grids.

Mat color

For most prints, bright white. It maximizes contrast, keeps the print as the focus, and never dates. Off-white or cream works for warm-toned prints and softer rooms but reduces contrast.

Colored mats (sage, navy, sand) are a strong stylistic choice — use sparingly and always pull the color from the print itself. A sage mat on a botanical illustration with sage in the foliage looks deliberate. The same mat on an unrelated print looks arbitrary.

Black mats are rare but work on white frames for high-key or ethereal prints. Avoid for anything else.

Single vs double mat

A double mat has two layers of board with a narrow strip of the inner color visible (often a thin black or colored line between the print and the main mat). This adds visual sophistication and is the standard for fine art framing.

Single mat for: posters, photography, most home framing.

Double mat for: hero pieces, fine art prints, anything where the framing itself is part of the statement.

Mat thickness

Standard mat board is 4-ply (about 1/16 inch) thick. This is fine for 95% of framing. For deeper-set looks (popular for photography and modern art), use 8-ply (about 1/8 inch) or stack two layers of 4-ply. Anything thicker requires a deeper frame rabbet — check the frame depth before ordering.

Acid-free and museum grade

For prints you care about long-term, specify acid-free mat board. Standard mat board contains lignin, which yellows and breaks down over time and can transfer onto the print itself. Acid-free (also called "conservation" or "museum grade") mat costs 2–3× more but keeps prints intact for decades.

If you're framing original artwork, signed prints, photographs you want to keep, or anything irreplaceable — pay for acid-free. For decorative posters you'll swap out in five years, standard is fine.

Common mat mistakes

  • Mat too narrow — print feels cramped, frame dominates.
  • Mat too wide — print feels lost, frame feels empty.
  • Cream mat with black frame — the contrast between cream mat and black frame fights the print.
  • No bottom weight on a portrait print — the print looks like it's sinking.
  • Colored mat that doesn't appear in the print — reads as arbitrary, not designed.

Get the mat right and the frame becomes invisible. That's the goal: the eye should land on the print first, the framing second.

Frequently asked questions

How wide should a mat be?

Scale it to the print, not a fixed width: 1.5 inches for a 5 x 7 in an 8 x 10, 1.5-2 inches for an 8 x 10 in an 11 x 14, 2.5 inches for an 11 x 14 in a 16 x 20, 2 inches for a 16 x 20 in a 20 x 24 and 3 inches for an 18 x 24 in a 24 x 30.

Can I get a mat board cut to size?

Yes — every mat we sell is cut to order, so the outer size and the opening are both made to your measurements rather than to a stock size. That is how you fit a non-standard print into a frame you already own.

What colour mat board should I use?

Bright white for most prints — highest contrast, keeps the print as the focus, never dates. Off-white or cream suits warm-toned prints. Only use a coloured mat if the colour appears in the print itself.

What is a weighted bottom mat?

The bottom margin is cut about 20% wider than the top and sides. It corrects an optical illusion — with equal margins a print looks bottom-heavy, because the visual centre of a rectangle sits above its geometric centre. Use it on portrait-orientation hero pieces, skip it on landscapes and grids.

Is acid-free mat board worth it?

For anything irreplaceable, yes. Standard mat board contains lignin, which yellows and can transfer onto the print. Acid-free (conservation or museum grade) costs 2-3 times more and keeps prints intact for decades.