Double matting and reveals: how to make a double mat

What a double mat reveal actually is

A double mat is a top mat laid over a second mat — the undermat — whose window is cut slightly larger. That size difference exposes a thin strip of the bottom board around the opening: the reveal. It reads as a slim accent border that frames your artwork in a second color.

A quarter-inch reveal is the classic choice — enough to register as a deliberate accent, never so wide it competes with the main border. The whole effect comes from one rule: undermat opening = top-mat opening + 2 × reveal. Everything past this point flows from that single line.

Why bother with a second board at all? A reveal does two quiet jobs. It separates a busy image from a plain mat with a calm transition, and it lets you echo a color from the artwork without committing the whole border to it. A blood-orange reveal under a cream mat picks up the warm tones in a photo far more elegantly than a full orange mat ever could. It's the framing equivalent of a pocket square — small, deliberate, and the thing people notice last but remember.

How it works: the formula, honestly

You only need two openings. The top opening is sized the normal way — the same math you would use for any single mat:

top opening = artwork − 2 × overlap

The overlap (typically ¼″) is the lip of mat that sits on top of the art on each edge so the piece can't slip through. Subtract it from both the width and the height. If that step is new to you, the mat border guide walks through choosing borders, and you can read off the exact window in the mat opening calculator.

The undermat opening is bigger by the reveal on every side. Because the strip shows top, bottom, left and right, you add the reveal twice to each dimension:

undermat opening = top opening + 2 × reveal

That's it. The outer (board) sizes of the two mats are identical; only the windows differ. Get your top-mat opening first, then add 2 × reveal — the mat border calculator handles the border-and-opening side of that for you.

One thing the formula hides: the reveal is measured on the face, the flat visible width of the strip, not along the bevel. Because both windows are cut at 45°, the cut edges are slightly longer than the face measurement — but you size to what the eye sees, so always work from the finished opening dimensions above, never from the bevel length. If your mat cutter is set up for the top mat, the only change for the undermat is moving each cutting guide outward by the reveal amount.

Worked example: an 8 × 10″ print

Say you're matting an 8 × 10″ print with the usual ¼″ overlap. Your top-mat opening is:

• Width: 8 − (2 × ¼) = 7½″
• Height: 10 − (2 × ¼) = 9½″

Now choose a ¼″ reveal. Add twice that — ½″ total — to each dimension of the top opening:

• Undermat width: 7½ + (2 × ¼) = 8″
• Undermat height: 9½ + (2 × ¼) = 10″

Notice the tidy result: the undermat window is exactly 8 × 10″ — the full print size. The top mat holds the art by its ¼″ lip, and the undermat simply frames the print edge with a ¼″ accent. It's a pleasing coincidence of this size, not a rule, but it shows the math working.

Choosing the reveal width

The reveal is the whole point of a double mat, so the width sets the mood. Narrow reads as a refined pinstripe; wider becomes a confident color band. Use this as a starting map, then trust your eye against the actual art.

Scale the reveal to the art, not to the frame. A small print drowns under a ⅜″ band, while a big poster makes an ⅛″ line vanish at arm's length. As a rough guide, use ⅛″ for small pieces, ¼″ as the common default, and ⅜″ to ½″ only when the art and main border are large enough to carry a stronger accent. If you can't decide, ¼″ is the answer nine times out of ten — it's the width professional framers reach for by reflex.

Double mats for needlework

Cross-stitch, embroidery and needlepoint often look better with a reveal because the accent can echo the thread color without putting a strong color across the whole mat. The catch is that stitched work is not held like a paper print. The fabric usually wraps around a mounting board or is laced behind it, so you must leave enough bare fabric outside the design before you think about the reveal.

Work in this order: size the stitched design and fabric margin first, decide how much blank fabric should show around the stitching, then size the top opening and undermat reveal. The cross-stitch framing calculator checks the design size, mat opening, frame size and lacing margin together, which is safer than borrowing paper-print overlap rules for fabric. For the full mount-and-frame walkthrough, see how to frame a cross-stitch.

How to make a double mat, step by step

1. Cut the top mat opening. Window = artwork − 2 × overlap. For our example that's 7½ × 9½″.
2. Pick a reveal and accent color. ⅛–⅜″, with ¼″ the safe default; choose the undermat shade that will peek through.
3. Size the undermat opening. Undermat = top opening + 2 × reveal — larger on every side. Here, 8 × 10″.
4. Cut the undermat window at that size, keeping a clean 45° bevel.
5. Stack and bond the top mat over the undermat, centered so the reveal is even on all four sides.
6. Mount the art behind both boards and assemble into the frame.

Common mistakes

• Cutting the undermat the same size as the top (or smaller). If the bottom window isn't larger, no reveal shows at all — you've just stacked two mats for nothing.
• Making the reveal too wide. Past about ⅜″ it stops reading as an accent and starts looking like a clumsy second border.
• A clashing accent color. The reveal is small but loud; pull a tone from the artwork rather than guessing a contrast.
• Forgetting the second board adds thickness. Two mats plus glass and backing may not fit a shallow rabbet — check depth, and add a spacer or a deeper moulding if needed.
• Mis-measuring so the reveal is uneven. If the top mat drifts off-center, the strip looks wider on one side; align carefully before bonding.

A few terms, defined

Framing vocabulary shifts between the US, UK and Australia. If a word here is unfamiliar, the matting glossary has the full list — including reveal, bevel and undermat.

Reveal

The strip of the bottom mat visible around the window; the accent the double mat exists to show.

Undermat (bottom mat)

The lower board, cut with the larger opening so its edge shows as the reveal.

Bevel

The 45° angled cut on each mat's inner edge; on a double mat you see two bevels stepping inward.

Mat / mount

The same board, different words — "mat" in the US, "mount" or "mount board" in the UK and AU.

Once you're comfortable, you can layer the same logic over a larger border or a bottom-weighted layout — the reveal math doesn't change. Read bottom-weighting explained to combine the two, then run your final numbers through the calculators.