QR code dpi for print vs vector

QR code dpi for print is how many pixels sit in each millimetre of the placed symbol, not how sharp a laptop screen looks. For toner paper, 300 dpi at the finished size is the usual brief. Vinyl and cutters want vector instead. Never upscale a preview capture.

QR code dpi for print is about millimetres, not megapixels

A 1200 px PNG is meaningless until you name the output width. Placed 2 cm wide, that file is already denser than a 300 dpi toner brief. Placed 20 cm wide, the same 1200 px file is about 150 dpi and the modules go grey. The millimetre-native raster is the one you export at the size it will print.

SmartQRCode download formats are PNG, JPG, SVG, and PDF. SVG and vector PDF scale without adding grey. PNG and JPG are rasters: they only stay crisp if you generate them at the millimetre-native raster size, or larger, then place them at 100 percent. The on-screen preview is not that file. It encodes /qr-preview. Do not screenshot it to skip paying, and do not screenshot it to fake dpi.

This procedure is for paper toner, inkjet, and digital shops that asked for a raster. It is the wrong procedure for a vinyl cutter. Dpi vs vector vinyl is settled: send paths.

A website QR code with a short hosted URL prints chunkier modules than a long static string in the same millimetre box. Density is a payload problem before it is a dpi problem. See SVG versus PNG when you are choosing the container, and vector for print when the shop asked for paths.

Export a raster at the finished millimetre size

1. Write the finished width in millimetres on the job ticket, quiet zone included in the box you will place.
2. Confirm the shop wants raster. If they said vinyl, cutter, offset, or flexo, stop and send SVG or PDF instead.
3. For paper toner or inkjet, export PNG or PDF at 300 dpi or higher, computed on that finished width. That is the 300 dpi toner brief.
4. Place the file at 100 percent in the layout. Do not stretch a 2 cm asset across a poster.
5. Keep modules 100 percent dark on a light ground. Do not flatten the symbol into a photograph of a table tent and reprint that photograph.
6. Print a proof on the real stock. Uncoated spread and gloss glare will not show in a screen preview.
7. Scan the proof with a phone camera. If modules look smoky, the file was upscaled or the dpi was computed on the wrong millimetre.

A logo in the centre is extra damage the error-correction budget must cover. Raising dpi will not recover a logo that already ate more modules than H can restore.

Is 300 dpi enough for a qr poster

Yes for coated or uncoated paper on a toner or inkjet device, if 300 dpi is calculated on the poster width, not on a thumbnail. A 400 px preview upscale to a 20 cm poster interpolates grey into every module edge. That grey is not a style. It is damage.

Large-format solvent shops sometimes ask for 150 dpi at full size because the viewing distance is metres, not 30 cm. QR is the exception in that brief. People still walk up and scan. Keep the symbol itself at the 300 dpi toner brief even if the surrounding photograph is 150 dpi. Better: place SVG in the poster file so the symbol is resolution-independent.

Minimum print size still applies. Dpi will not save a 2 cm mark meant to be read from the street.

Why an upscaled png turns grey

Raster math averages neighbouring pixels when you enlarge. QR modules must stay binary. The camera is looking for a sharp dark-light grid, finder squares included. Interpolation creates mid-greys the decoder treats as dirt.

JPG is worse than PNG for this because the codec already adds block artefacts around high-contrast edges. If you must send raster, PNG or a PDF that embeds a high-resolution bitmap beats JPG. SVG still beats both.

Flattening a photo of a printed code and sending that photo to a second press is a second generation of blur. Each generation adds grey. Start from the original download.

Raster failures on gloss and uncoated

Uncoated stock drinks ink; modules spread. A 300 dpi file on newsprint can still choke because the physical dots grow. Compensate with size or stock, not with a 600 dpi file of the same 15 mm symbol. Gloss coated stock reflects overhead light. A code that scans on a desk can fail on a table under a downlighter. Matte laminate on the symbol, or a less glossy varnish there, is the press fix. Dpi does not kill glare.

Packaging flexo is not a dpi conversation. Flexo wants vector and a formed-pack scan. A millimetre-native raster of a flat proof will not tell you what a shrink curve does to module pitch.

Each generation of that photograph adds blur the decoder treats as dirt. If the shop asks for a flattened PDF, flatten from the SVG master at the end, not from a phone photo of a printed sample.

A millimetre-native raster is also how you stop a well-meaning operator from "enhancing" the code in Photoshop. Sharpen filters create halos. Blur filters fill alleys. Levels that crush blacks can merge neighbouring modules. The RIP wants a binary grid. Give it one.

How a digital toner shop still mangles a 300 dpi file

The file was 300 dpi on a 2 cm thumbnail, then placed at 8 cm. The ticket said 300 dpi and everyone believed it. Write the placed width next to the dpi number. If the shop uses a hot folder that downsamples to 150 dpi for photographs, exclude the QR layer. Ask them to RIP the symbol as a solid, not as a photo.

Uncoated letterheads in that same shop will still spread. Dpi does not cancel fibre swell. You may need both 300 dpi and a larger millimetre. Gloss invitations in the same run may glare under banquet lighting. Test the actual room.

Minimum print size and dpi are separate dials. Turning one does not turn the other.

When you should skip dpi and send SVG

If the shop has a vinyl cutter or a laser, a PNG will be traced. Tracing QR modules produces broken corners. Send SVG. If the job is offset or flexo with a spot dark ink, send vector and treat dark modules as 100 percent of that ink, not a four-colour build. If the job is a one-off A4 that will never be edited or counted, a Canva static PNG at the real millimetre size is enough. SmartQRCode does not sell an unpaid plan. Use $1.99 or $97 when you need a hosted destination you can still change; use a free static generator when you do not.