Can I just increase the DPI in Photoshop?

Not usefully. Changing the DPI number without resampling only changes the label; the pixels are still the pixels. Resampling up invents pixels that were never captured, which is why upscaled images look soft or mushy on paper. The only real fix is a larger original - re-export from the source file, re-shoot, or use vector artwork, which has no resolution at all and prints crisp at any size.

What is bleed, and why does my printer keep asking for it?

Bleed is artwork extended past the trim line - about 0.125 inch (3 mm) on each edge. Guillotines and trimmers move by a fraction of a millimetre, so if your background stops exactly at the trim line, any drift leaves a thin white sliver down the edge. Bleed gives the cutter something to eat into. Keep anything important - text, logos - at least 0.125 inch inside the trim, in what is called the safe area.

Does it matter if my file is RGB instead of CMYK?

Yes, though not fatally. Screens make colour with light (RGB); presses make it with ink (CMYK), and the ink gamut is smaller. Bright screen blues, vivid oranges and neon greens have no CMYK equivalent, so they get mapped to the nearest printable colour and can look duller than you expected. Converting to CMYK yourself means you see that shift and can correct it, instead of being surprised by the proof.

Which file format should I send to a print shop?

A flattened, print-ready PDF is safest - it carries fonts, bleed and colour settings in one file. High-resolution JPG, PNG or TIFF are fine for simple single-image jobs. Avoid sending native files (PSD, AI, INDD) unless your shop asks, and avoid anything pulled from a website or a social post - those are compressed for screens and almost always too low-resolution to print.

Is this the same as a professional preflight?

No, and we would rather say so. This is a quick sanity check on the things that go wrong most often. A real preflight also inspects colour profiles, overprint settings, spot colours, transparency flattening, hidden layers and trapping. Treat this as a way to catch the obvious problems before you send a job - not as a guarantee it will print perfectly.

Free tool · No upload, nothing leaves your browser

Is your file print-ready?

The number one worry before any job: will it print right? Drop in an image to check its resolution for your print size, then run the quick checklist. Everything happens in your browser - your file is never uploaded.

Illustration of a loupe magnifier over a printed sheet revealing crisp halftone dots and crop marks, with three check marks beside it

Step 1

Check resolution

Drop in an image and tell us how big you’re printing it.

Drag an image here, or click to chooseJPG, PNG, GIF, WebP - stays on your device

Print width (in)

Print height (in)

Step 2

Tick the checklist

0/6

Six things that catch print jobs out again and again.

300 DPI resolution at final sizeEnough pixels so it prints crisp - not blurry. Use the checker above.
CMYK colour modePrint uses CMYK inks. Files set to RGB (screen colour) can shift on press.
Bleed added (about 0.125")Extra artwork past the edge so trimming doesn’t leave a white sliver.
Fonts outlined or embeddedSo your text prints in the right font even if we don’t have it installed.
Correct trim / finished sizeThe artwork is built to the exact size the job is meant to finish at.
Right file format (print-ready PDF, or high-res image)A flattened PDF is safest. High-res JPG/PNG/TIFF work for simple jobs.

Run through the checks

Drop in a file and tick off the list to see where you stand.

This is a quick guide, not a professional preflight - it can’t catch everything (colour profiles, overprint, hidden layers) and it doesn’t guarantee your file will print perfectly. When in doubt, ask your print shop.

What DPI actually means

Why resolution trips people up

DPI is just how many dots (pixels) land in each printed inch. A photo that looks crisp on a phone screen can come out soft on paper, because print packs far more detail into the same space. The fix isn’t magic - it’s having enough pixels for the size you’re printing.

300+ DPI

Sharp for anything held in the hand - cards, flyers, brochures.

150–299 DPI

Fine for big or far-off prints like posters and banners.

Under 150 DPI

Will likely look blurry or blocky up close. Get a bigger file.

Stop fixing files for free

Let the file come in print-ready

Chasing bad files is one of the biggest time-sinks in a print shop. When customers design on your store, Printmio exports a print-ready 300 DPI CMYK PDF automatically - the artwork lands ready to print, not as a low-res screenshot you have to rescue.

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Questions we get asked

300 DPI at the final printed size is the safe answer for anything held in the hand - business cards, flyers, brochures. Large-format work you view from a few feet away, like posters and roll-up banners, is usually fine at 150 DPI. The catch is "at final size": a 300 DPI image is only 300 DPI if you print it at the size it was made for. Blow it up and the DPI drops in proportion.

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A 30-minute screen share built around how your shop quotes, proofs and prints. We approve every founding shop personally and set it up with you - no credit card, no setup fee.

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