Shadow Box Frame Guide: Sizes, Depth & Mounting

A shadow box frame is a picture frame with a stage

A shadow box frame is a deep display frame: a clear front panel, a fabric-lined backing, and 3-8cm of enclosed space between them. That depth is the entire point — it holds three-dimensional objects a flat picture frame physically cannot close over: folded jerseys, medals, dried flowers, memorabilia.

The name comes from what the depth does visually. An object sitting in open space behind the front panel throws a soft shadow on the backing, and that shadow reads as importance — the same trick a museum vitrine plays. A picture frame presses its contents flat against glazing; a shadow box frame gives its contents a stage. Everything else about the product — depth, front material, backing, mounting — is a variable you choose around the object going inside.

The market splits the same object into two builds, and it helps to know both names. Frame-style shadow boxes look like a thick picture frame: a visible border profile around a shallow recess, usually for flat-ish objects given room to breathe. Box-style shadow boxes are what we build most at Wetop — five bonded acrylic walls and a clear face, with the fabric backing panel closing the back — which reads cleaner at larger sizes and deeper recesses. Both hang on a wall; both answer to the same depth math. This guide covers the decisions in the order they should be made: depth first, front material second, frame-versus-box third, then how the object mounts inside and how the whole thing mounts to the wall.

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Choose the depth from the object, not the catalog

Depth is a measurement, not a style choice: take the object’s tallest point off the backing and add 1-2cm of clearance so nothing touches the front panel. That lands at 3cm for medals and pressed flowers, 5cm for flat-folded jerseys and dried bouquets, and 8cm or more for draped jerseys and helmets.

Both failure directions cost money. Too shallow and the object touches the front panel — a jersey pressed against acrylic wicks a faint contact mark into view within weeks, and a bouquet loses petals to every vibration of the wall. Too deep and the display reads hollow: a flat medal in an 8cm recess looks like it’s at the bottom of a well, and the order has paid for material, freight volume, and wall projection it didn’t need.

For coins and small round collectibles, the coin display layout ideas extend this depth check to grouped layouts, profile-matched recesses, and felt liners.

What you’re framing	Height off backing	Recess depth	Typical frame size
Medals, coins, patches, pressed flowers	Under 2cm	3cm	20x20 to 30x40cm
Flat-folded jersey (name and number showing)	2-4cm	5cm	60x80cm
Dried wedding bouquet, invitation set	2-4cm	5cm	40x50cm
Draped jersey, full-front display	4-7cm	8cm	80x100cm
Helmet, ball, multi-item arrangement	5cm+	8-10cm+	Sized to layout

One production note from my side of the process: depth changes the build more than buyers expect. When my operators bond a 3cm frame, the side walls behave like an ordinary frame profile. Past 5cm the walls become structural panels — they carry the front, resist racking, and show every bonding flaw at eye level — which is why deeper frames also get thicker walls in the construction section below.

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Standard shadow box sizes

Shadow box sizes follow standard picture-frame formats: 5x7, 8x8, 8x10, 9x9, 11x14, 12x12, 16x16, 16x20, 18x24, 20x20, and 24x36 inches are the sizes framers and retailers stock, with 8x8, 11x14, and 16x20 the most common. The acrylic frame size chart separates print, opening, and outer-panel dimensions for those shared face formats. Depth is what separates a shadow box from a picture frame at the same nominal size.

The list exists for supply-chain reasons, not display reasons: mats, backing boards, and replacement fronts are cut to those formats, so off-the-shelf shadow boxes cluster around them. The table maps each standard size to the depth and contents this guide’s rule would assign it.

Nominal size (in)	≈ Metric (cm)	Typical recess depth	Commonly framed
5x7	13x18	3cm	Single medal or coin, small keepsake
8x8	20x20	3cm	Pressed flower, baby memorabilia
8x10	20x25	3cm	Medal cluster, photo + object pairing
9x9	23x23	3-5cm	Square keepsake art, medal cluster
11x14	28x36	3-5cm	Certificate + medal, invitation set
12x12	30x30	3-5cm	Square art, baby keepsake grouping
16x16	41x41	5cm	Multi-item keepsake layout
16x20	41x51	5-8cm	Dried bouquet, medal career display
18x24	46x61	5-8cm	Large botanical, mixed memorabilia
20x20	51x51	5-8cm	Square bouquet display
24x36	61x91	5-8cm	Flat-folded jersey, signed poster + memorabilia

For a custom manufacturer the list is a reference, not a constraint. Buyers may submit an imperial catalog format such as 16x20 or the object’s measured dimensions. The quote should compare the required material, cutting, backing, hardware, packing, and quantity rather than assume standard and custom dimensions cost the same. Work in whichever unit the program uses; the acrylic shadow boxes page shows additional format guidance.

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Acrylic front vs glass front

Cast acrylic runs about 1.18g/cm³¹ against roughly 2.5g/cm³ for soda-lime glass,² so an equal-size acrylic panel weighs about half as much. Failure behavior depends on the named grade, thickness, support, edge condition, mounting, and finished construction; do not treat either material as unbreakable.

Weight compounds with the backing, side walls, object, and hardware. A 60x80cm front is 0.48m², so density changes the finished mass and may affect packing and mounting. Compare the complete assemblies: acrylic is generally less scratch-resistant than glass, while impact behavior varies by grade and construction. Keep protective film in place through installation and follow the named sheet maker’s approved care method.

Spec	Acrylic (cast PMMA) front	Glass front
Density	~1.18g/cm³	~2.5g/cm³
60x80cm x 3mm panel weight	~1.7kg	~3.6kg
Failure mode	Grade- and construction-specific; generally more impact-resistant than annealed glass	Annealed, tempered, and laminated glass fail differently
UV protection	UV-filtering grade available	Standard glass: minimal; UV glass: costly
Scratch resistance	Lower — film + microfiber care	Higher
Clarity	~92% light transmission	Comparable

UV deserves its own sentence because shadow box contents are usually irreplaceable. Signed fabric, certificate ink, and dried botanicals all fade under light exposure — the Library of Congress’s framing guidance is blunt that light damage to displayed originals is cumulative and irreversible³ — so for anything signed or sun-exposed we quote UV-filtering acrylic as the front panel. The acrylic yellowing, UV-grade, and frame-care guide explains what to request from the sheet datasheet and cleaning plan. The full glazing comparison, including the picture-frame side of the argument, is in our acrylic vs glass picture frame guide.

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Frame-style or box-style — and when you want neither

Pick frame-style when the object is flat and the look should read as framing: a floating border, minimal profile, art-gallery language. Pick box-style when the object is genuinely three-dimensional and needs a fabric backing, pins, or compartments. Pick a display case instead when viewing is from multiple sides.

The frame-style build shines on flat and near-flat pieces — textile fragments, embroidered art, invitations, a single pressed arrangement — where the modern treatment is a floating presentation: the piece held between panels or against a back panel with a clear border of open acrylic around it. That’s the construction behind our acrylic floating frames, and it pairs naturally with magnetic closures for pieces that rotate. The magnetic picture-frame format and closure guide compares that assembly with other frame constructions.

The box-style build takes over as soon as the object has real depth or real weight. Five bonded walls, a velvet or felt backing panel, and interior mounting hardware make an 8cm-deep, 80x100cm jersey display rigid enough to hang for years — a border-profile frame at that depth would look like a crate. Our acrylic shadow boxes page covers the box-style formats, backing options, and jersey layouts in detail.

And sometimes the honest answer is neither. If buyers will walk around the object — sneakers, helmets, model cars on a counter or pedestal — a wall-view shadow box frame is the wrong product; a freestanding display case with 10cm-plus depth and hinged or lift-off access serves the viewing pattern the wall never can.

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Mounting the object inside

Objects mount to the backing, never to the front: stainless pins and T-pins for fabric, sewn or magnetic strips for jerseys, wire cradles for hardware, and pressure or magnet systems for paper art. The front panel stays a window — nothing adheres to it.

Fabric is the forgiving case. A jersey pins to a velvet backing invisibly, and velvet’s nap hides pin entry points; cork backing takes pins directly for medal groups that may be rearranged. Rigid objects — a game ball, a champagne flute, a piece of hardware — get formed acrylic cradles bonded to the backing so the object rests in shaped support instead of hanging from a fastener.

Delicate flat art is the demanding case, and it’s a request I see from museum and fine-art buyers a few times every quarter: original paper or embroidered pieces that cannot be glued, taped, or pierced. The working method is mechanical, reversible hold — the piece sits against the backing and a magnet system through the backing panel holds mounting strips, or the front assembly applies gentle even pressure through a mat border. Two numbers make the floating look work: leave a 3-5cm clear border of open backing around the piece so it reads as floating, and keep magnet positions clear of the artwork itself so nothing presses the original. For a fragile piece, that’s precisely what the pre-production sample is for — we mount a stand-in of the same weight and size and photograph the result before the original is ever committed. We ran this exact border-and-magnet engineering at gallery scale in our colored acrylic floating frames for art galleries case study.

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Hanging it: wall hardware is a load spec

Match the hanger to the finished weight, wall substrate, anchor, fastener, required safety factor, and installation method. The acrylic frame mounting guide compares standoffs, magnets, easels, and cleats before the drawing is approved. Their rating must come from the approved hardware and substrate test evidence rather than a universal frame threshold.

Calculate the finished mass before selecting hardware. The mounting engineer or hardware supplier should evaluate the frame, object, wall substrate, anchors, fasteners, installation access, and safety factor as one system. Keyholes, cleats, standoffs, and direct-to-structure anchors can suit different projects, but this guide does not assign a universal weight cutoff to any one method.

If hardware or a drilling template is required, list it in the quote, approved sample, packing specification, and installation instructions. Do not assume those items are included unless the order documents say so.

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Construction specs that keep a shadow box frame flat

Standard construction is a 3mm acrylic front with 5mm side walls and a 3mm backing panel. Past 60cm on the long edge, or past 500g of mounted object weight, step to a 5mm front and 8-10mm walls so the frame stays flat and rigid on the wall for years.

Depth is what separates this from ordinary frame engineering. The side walls of a deep frame are beams: they hold the front panel parallel to the backing across the whole span, and any bow in them telegraphs to the front as visible distortion. Twelve years of running these builds have settled me on a simple discipline — thickness follows the long edge, not the nominal size class. A 40x50cm bouquet box is comfortable at standard spec; a 60x80cm jersey frame gets the 5mm front; an 80x100cm draped display gets 8-10mm walls without discussion. Bonded joints follow the same logic: full-length solvent-welded seams rather than spot bonds, because a wall-hung frame is a permanent static load test that never ends. The span-versus-thickness math generalizes across products — our acrylic thickness guide works the numbers if you’re speccing an unusual size.

Backing choice finishes the spec: black velvet for contrast and pin-friendly mounting, colored felt for team and brand palettes, cork for re-pinnable medal groups, and mirrored acrylic when the back of the object matters. UV-filtering front grade, engraved nameplates, and UV-printed graphics ride along in the same production run.

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Ordering shadow box frames in bulk

Bulk shadow box frame orders start at 100 pieces per design, with samples in 3-5 days and production in 15-20 days. Send the object’s dimensions — or a photo with a ruler in frame — plus quantity and backing preference, and you get a full spec and quote within 24 hours.

The sample stage matters more here than on most products because the object is usually one-of-a-kind. We build the frame around a stand-in first: you confirm depth clearance, backing color, and mounting method on the sample, then the production run repeats it fifty or five hundred times under 100% inspection in our ISO 9001-certified factory. Team programs, memorabilia retailers, florists preserving wedding bouquets, and award programs all run on the same cadence — one approved sample, then repeatable volume, FOB Shenzhen with CIF and DDP available.

Start with the object: measure its footprint and its tallest point, decide flat-fold or draped if it’s fabric, and send us the numbers. We’ll answer with depth, thickness, backing, and mounting specs already filled in — the decisions this guide just walked through, applied to your piece.

Footnotes

1. Polymethylmethacrylate (PMMA / Acrylic) material properties — MakeItFrom — independent materials database listing PMMA density (≈1.2 g/cm³ rounded; industry datasheets run 1.18-1.19), the value behind this guide’s front-panel weight comparison. ↩

2. Soda-lime glass material properties — Imetra — engineering reference displaying soda-lime glass density of about 2.5g/cm³, anchoring the roughly 2:1 weight ratio between glass and acrylic shadow box fronts. ↩

3. Preservation Guidelines for Matting and Framing — Library of Congress — national preservation guidance stating that light exposure causes permanent, irreversible fading and discoloration in displayed paper-based materials, the basis for recommending UV-filtering front panels over signed and printed contents. ↩