300 DPI for sublimation, explained
DPI is the most misunderstood number in sublimation, and it causes two very different problems: files that are genuinely too low-resolution, and files that are fine but open at the wrong size. Here is how to tell them apart.
Pixels are the thing. DPI is a label.
An image file contains a fixed grid of pixels. That grid is all the detail that exists. DPI (dots per inch) is a separate number stored alongside it that says how densely to lay those pixels down when printing — in other words, how many inches wide the image should come out.
One formula connects them, and it is the only one you need:
pixels = inches × DPI
So a template that has to print at 9.32″ × 8.13″ needs 2798 × 2438 pixels to be a genuine 300 DPI file. Fewer pixels than that, and it is not 300 DPI no matter what the file says.
What 300 DPI means for real wrap sizes
| Blank | Wrap size | Pixels needed at 300 DPI |
|---|---|---|
| 20 oz Skinny Straight Tumbler | 9.28″ × 8.2″ | 2785 × 2460 px |
| 20 oz Skinny Straight — MakerFlo | 9.32″ × 8.13″ | 2798 × 2438 px |
| 11 oz Sublimation Mug | 8.5″ × 3.5″ | 2550 × 1050 px |
| 20 oz Thick (Fatty) — MakerFlo | 11.2″ × 7.72″ | 3360 × 2318 px |
The size chart has this column for all 32 blanks.
How to check a file in under a minute
- Windows: right-click the file → Properties → Details. Read Image width, Image height, and Horizontal/Vertical resolution.
- macOS: open in Preview → Tools → Show Inspector. The General tab lists both the pixel dimensions and the DPI.
- Photoshop / Affinity Photo: Image → Image Size. Uncheck Resample and you can read the true relationship: change the inches and watch the DPI move, with the pixel count frozen.
- Anywhere: divide. Pixel width ÷ intended print width in inches = your real DPI. If a seller’s "300 DPI" wrap for a 9.32″ × 8.13″ blank is only 2000 px wide, it is 214 DPI.
The missing-metadata trap
This is the one that catches people out, because nothing looks broken. PNG stores physical size in
an optional chunk called pHYs. Screenshots, most web exports and plenty of template shops
omit it. When an app opens a PNG with no pHYs, it has to guess, and the near-universal
guess is 72 DPI.
The practical result: a perfectly good 2798 × 2438 px wrap lands on your Procreate or Silhouette Studio canvas at about 38.9″ wide instead of 9.32″. You scale it down to fit, the design prints fine, and you never learn why the first import looked absurd. But if you scale by eye rather than to an exact size, the wrap ends up slightly wrong — and that shows at the seam.
Why our PNGs behave. Every PNG this generator exports has a pHYs
chunk written at 300 DPI, so it opens at its true physical size in Procreate, Photoshop, Canva and
Silhouette Studio with no rescaling and no guesswork. The SVG export carries real inch units for the
same reason.
Why retyping "300" fixes nothing
Setting the DPI field to 300 does one of two things. If resampling is off, it re-labels the same pixels — the file now claims 300 DPI and prints smaller, which is honest but not what you wanted. If resampling is on, the software generates new pixels by interpolating between existing ones. It has no information about what was between them, so it averages. The result is a bigger file that is softer, not sharper, and text edges are where it shows first.
The only real fix is to start with enough pixels: use vector artwork where you can, buy raster assets at the size you will print them, and generate templates at the final wrap size rather than resizing them afterwards.
Download a true 300 DPI template →
FAQ
What does 300 DPI actually mean?
It means 300 pixels are packed into each printed inch. DPI on its own says nothing — it is only meaningful alongside a physical size. A 9.32″ × 8.13″ wrap at 300 DPI is 2798 × 2438 pixels; the same pixels labelled 150 DPI would print at 18.65″ wide.
How do I check the DPI of a PNG?
On Windows, right-click the file, choose Properties, then the Details tab, and read Horizontal/Vertical resolution. On a Mac, open it in Preview and choose Tools → Show Inspector. In Photoshop or Affinity, Image Size shows resolution and pixel dimensions together. The pixel count is the number that matters — the DPI label just tells the app how big to open it.
Why does my template open at the wrong size in Procreate or Silhouette Studio?
Because the PNG has no resolution metadata. A PNG stores DPI in an optional chunk called pHYs, and many exporters simply leave it out. Apps then fall back to 72 DPI, so a 2798 × 2438 px wrap opens as roughly 38.9″ wide instead of 9.32″. Nothing is wrong with the pixels — the file just forgot to say how big it was.
Can I raise a low-resolution file to 300 DPI?
Not meaningfully. Re-labelling changes the number without changing the image. Resampling upward makes the software invent pixels by interpolating between the ones you have, which produces a larger, softer file rather than a more detailed one. Start from artwork with enough pixels for the final print size.
Is 300 DPI always necessary?
It is the standard target for sublimation, and it is the right default for anything with fine lines, small text or crisp edges. Large soft artwork — watercolour washes, gradients, photographic backgrounds — tolerates less, and many crafters print those below 300 without a visible difference. When in doubt, aim for 300: you can always throw resolution away, and you cannot get it back.