Custom Size Poster Printing: How We Fit Any Print to Your Frame

Got a frame that refuses to match anything sold in stores? Send us its exact measurements and we'll check whether the piece you want can be repositioned onto the next matching paper size, so nothing important gets lost once it's trimmed down to fit. This isn't a checkout option you configure yourself. It's a made-to-order request we handle by hand for every customer who asks, and we always show you the placement before anything gets printed.

Here's how far that can go. The frame below has an opening of just 18 x 39.5 cm, a long, narrow panorama shape that doesn't exist as a standard poster size anywhere. We repositioned the chosen artwork onto the next matching sheet and confirmed it with the customer before printing, so the composition stayed intact once it was trimmed to that exact size.

That's the most extreme example we've handled, and it's here purely to show what's possible. The rest of this page walks through a different, complete job from start to finish: fitting one of our prints into a frame that turned up with no back panel at all.

In this article

• How custom size poster printing actually works here
• Step 1: Measure the frame's actual opening, not the outside
• Step 2: Send us your measurements before you order anything
• A note on secondhand and antique frames
• Step 3: Build a back panel if the frame doesn't have one
• Step 4: Give the frame itself some attention (optional, but worth it)
• Step 5: Trim your print to the exact measurement once it arrives
• Step 6: Mount the poster to the back panel
• Step 7: Close the frame
• Common mistakes people make with custom size prints
• FAQ

How custom size poster printing actually works here

We don't print to one bespoke millimeter size at checkout, and honestly, no shop really does that well. What we do instead is keep a fine ladder of standard sizes, from 13 x 18 cm up through A4, A3, A2, A1, and A0 (84.1 x 118.9 cm), and when your frame falls between the cracks, we place your chosen artwork onto the next matching sheet ourselves, positioned so nothing gets cropped out when you trim it down.

Not every piece can be adapted this way. A composition built for a square canvas doesn't always survive being pushed into a tall, narrow panorama without losing what made it work in the first place. That's exactly why this is always a task we do on request rather than something automated: we check the artwork against your measurements first, and you get to see the placement before you commit to an order.

Step 1: Measure the frame's actual opening, not the outside

This is the step people skip, and it's the one that ruins everything downstream. Measure the visible opening where the artwork actually sits, not the outer edge of the frame and not the glass if there is one.

Quick tip before you lock in your custom size: measure the actual frame opening, then add a little extra on every side – about 3 - 5 mm does the trick.

Here's why. The opening is the "keyhole" your print peeks through, not the print's actual size. Cut the print to match the opening exactly, and the tiniest shift during mounting leaves a sliver of white edge showing – the kind of gap that'll haunt you more than anything printed on the paper. Size it a bit larger, and the artwork tucks in cleanly behind the opening no matter which way the panel settles.

Use a tape measure or folding rule, check both the width and height, and measure twice from different corners since old frames are rarely perfectly square.

Write both numbers down before you contact us. IMO this single step prevents 90% of the back-and-forth in a custom size request.

Step 2: Send us your measurements before you order anything

Message us your two measurements and the piece you have in mind. We'll tell you whether it's a straightforward fit or a stretch, place the artwork onto the correct paper size ourselves so the important parts of the composition survive the final trim, and send that placement back to you to check before we print anything.

This step is what separates a custom fit from a disappointing one. Order a standard size on your own and trim it blind, and you risk cutting straight through a face, a hand, or whatever detail makes the piece worth hanging in the first place. Sending us the measurements first means someone actually looks at the composition before a blade goes anywhere near it.

A note on secondhand and antique frames

Some of the best frames for dark, moody art aren't sold new anywhere, they're found. Flea markets, estate sales, and that one dusty corner of a secondhand shop tend to produce frames with actual character: carved detail, aged gilding, proportions nobody manufactures anymore. The tradeoff is that these frames often arrive incomplete.

This particular frame had no back panel at all, which is common with older frames that have changed hands a few times. Often it's because the frame started life holding a mirror rather than art. Once the glass cracks, the mirror gets tossed, but the frame is too nice to throw out with it, and the backing tends to disappear somewhere along the way. That's not a dealbreaker. It just means the next step isn't optional.

Step 3: Build a back panel if the frame doesn't have one

A thin sheet of plywood does the job. Lay the frame face down, use a carpenter's square to mark a true right angle from one corner, and measure out to match the frame's outer rabbet (the little ledge the backing sits in, just inside the outer edge).

Cut along your lines with a jigsaw, staying just outside the pencil mark so you can sand or trim down to a perfect fit rather than ending up slightly too small.

Once it's cut, test-fit it against the frame before moving on. A back panel that's even a couple of millimeters too big will bow the frame's corners over time.

Step 4: Give the frame itself some attention (optional, but worth it)

You don't have to touch the frame's finish. But if you've found something with decades of grime, mismatched gilding, or a color that clashes with the piece you're framing, this is the moment to fix it. For this job, the original gold finish was repainted using a matte chalk paint.

One coat of matte chalk paint later, the frame goes from "grandma's hallway" to something that actually suits a dark art print.

For a worn, antique look rather than a flat new-paint finish, lightly scuff or scratch the paint back at the raised details while it's still wet. This lets the original gold underneath peek through, which reads as genuine age rather than a fresh repaint.

Step 5: Trim your print to the exact measurement once it arrives

Once your print arrives, already positioned so the composition has room to spare, lay it face up on a cutting mat with a metal straightedge ruler along your cut line. A snap-off utility knife with a fresh blade gives a cleaner edge than scissors, especially on thicker fine art paper stocks. Score the line in two or three light passes rather than trying to cut through in one go.

Fresh prints tend to curl slightly from being rolled for shipping. If yours does, rest a couple of straight wooden battens or dowels across it while you work. This isn't part of the frame, it's just a weight to hold the paper flat so your measurements stay accurate while you cut.

Step 6: Mount the poster to the back panel

Lay the trimmed poster face up on your back panel and check the borders are even on all sides before you commit to anything sticky. A spirit level laid across the top works well here too, mostly just as a straight, heavy edge to hold the paper down while you line it up.

Tape along the edges and a strip or two through the middle is enough to keep the poster flat for years without warping the paper the way a full sheet of adhesive can.

Step 7: Close the frame

Slide the mounted panel into the frame's rabbet and secure it with a few small nails or points tapped in at an angle along the inner edge, the same way most factory-made frames are finished. That's it. The poster is now sized, mounted, and protected inside a frame that fits it exactly.

Common mistakes people make with custom size prints

• Measuring the outer frame instead of the inner opening. The outer dimension tells you nothing about what size print will actually sit inside it.
• Ordering a standard size and trimming it blind, without checking with us first. Without repositioning the artwork on the sheet, a blind trim can cut straight through the part of the image that matters.
• Assuming any design can stretch into any aspect ratio. Some compositions hold up fine as a panorama, others don't. That's exactly why we check before printing.
• Assuming a secondhand frame has a back panel. Plenty don't, especially ones that started life holding a mirror. Once the glass breaks, the backing usually goes missing along with it.
• Skipping the flattening step. Rolled prints curl. Trim a curled print without flattening it first and your straight lines won't stay straight.
• Covering the whole back panel in adhesive. Full-sheet adhesive can cause paper to ripple over time. Edges plus a couple of interior strips hold just as well and lay flatter.

Frequently asked questions

Can I get a poster printed in a completely custom, non-standard size?

Not as a direct print run at your exact millimeters, no. Send us your frame's measurements and the piece you want, and we'll place the artwork onto the next matching standard size ourselves, positioned so nothing important is lost once you trim it down. This is a made-to-order request, not an automatic checkout option.

Does every poster design work for an unusual or panorama-shaped frame?

No. Some compositions can be repositioned into a tall, narrow, or unusually shaped canvas without losing what makes them work, and some can't. That's why we check the specific piece against your measurements first and show you the placement before printing anything.

Do I need to work out the size myself?

No. Measure your frame's inner opening in both directions and send us those two numbers along with the piece you have in mind. We'll handle picking the right paper size and positioning the artwork on it.

Is there a minimum order for a custom size request?

No. A single print is enough. There's no minimum quantity requirement for a custom placement.

What tools do I need to trim a poster to size once it arrives?

A cutting mat, a metal straightedge ruler, and a sharp utility or craft knife. A tape measure and a carpenter's square help too if you're also building a back panel.

Will trimming the poster damage the print quality?

No, as long as the artwork was positioned correctly first. That's the entire point of sending us your measurements before ordering: the trim line only removes blank or excess border area, never the image itself.

Can you help restore or refinish an old frame too?

We can't take in physical frames for restoration, but the process shown above (repaint, distress, replace the back panel) is something most people can do at home in an afternoon with basic tools and craft paint.