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A QR code on a plate is a decision you make once and live with for years. These are the settings QRtub recommends, and the reasoning behind each — so you can put them on a print spec and defend them.

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The standards, in short

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Format: SVG unless it is going on a screen

SVG is vector, so the same file prints at 20 mm on a tool tag or 400 mm on a plant room door with identical edges. It is the right choice for every supplier handoff. PNG is a fixed grid of pixels — QRtub exports it at 1024 × 1024. That is roughly 87 mm at 300 dpi, which is fine for a tag or a sticker and not enough for a sign. Enlarge a PNG well past that and the module edges soften until the code stops decoding. Use PNG for a web page, an email, a slide.

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Error correction: Q for print, and do not shop on size

Error correction is how much of the code can be destroyed and still scan — roughly 7% at L, 15% at M, 25% at Q and 30% at H. Those figures come from the QR standard and do not change. Choose by where the code is going, not by how big the code comes out. Raising the level can add modules, which at a fixed physical size makes each module smaller — but how much, or whether at all, is genuinely unpredictable. It depends on the length of the address, whether the slug happens to contain digits, and which domain the code encodes. The same Link produces a different code on qrtub.com than on the shorter qrt.au. That unpredictability is the reason not to optimize here. The difference between levels is at most a step or two of module count, which a phone camera does not notice at a sane printed size — while the difference between 15% and 25% damage tolerance is what decides whether a scratched plate still works in year eight. Take Q and spend your attention on size and material instead, which are where printed codes actually fail. Error correction protects against damage, not against a code printed too small. A pristine 10 mm code at H still will not scan reliably. Size first, then error correction.

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Quiet zone: 4 modules, and nothing crosses it

The blank border around the code is what the scanner uses to find its edges. Four modules on all four sides, and nothing in it — no logo, no border, no text, no mounting hole, no laminate edge. QRtub exports a 4-module margin, so a placed file already carries its quiet zone. What it cannot do is protect it. Anything your layout puts inside that border — a rule, a rivet, a trim edge — takes the clear space back. Mark the boundary on the spec, not just the code’s position. Full detail in Quiet Zone and Minimum Size.

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Color: black on white

Black on white is the only combination guaranteed to work, because a camera reads contrast rather than color. QRtub exports black on white and does not offer brand colors — a code in your brand’s mid-tone on a light background can look right and fail in poor light.

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Transparent background

The export offers a transparent background as a deliberate choice. It removes the QR code’s background so it can be placed over other artwork — a colored substrate, an anodized plate, an existing label design. Take it only when you control what ends up behind the code, because the white background is not decoration. It is the quiet zone, made physical. Turning it off hands responsibility for both contrast and clear space to whoever places the artwork, and the failure arrives late: a transparent code looks correct on a white screen and disappears into a dark plate.

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Where the logo goes

Beside the code, above it, or below it — not inside it. A logo in the middle of a QR code works by destroying modules and relying on error correction to reconstruct them. That is the same budget you provisioned for grit, scratches and a decade of UV. Spending it on branding means the code leaves the shop already partly consumed, and the first real damage is the damage that breaks it. There is no reserved space in the middle of a QR code. Unlike the three corner squares, the center is live data. A logo outside the code costs nothing, can be considerably larger, and stays legible from further away than the code can be scanned from anyway. On a plate with room for both, that is the better design as well as the more durable one.

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Print the address as text too

Put the Link’s address in readable text near the code — qrtub.com/cra0042tl under a code, or CRA0042TL as the plate’s own number. It is the fallback when the code is unreadable, and with a numbered Link it does double duty: the plate number and the web address are the same string, so there is one identifier instead of two and nothing to map back to a spreadsheet. See Choosing a Link Type.