Notes
Vector vs raster: what survives a garment size run
The same file prints larger on a 3XL than on a small. If it was only just sharp enough at the base size, it is not sharp enough at the top of the run — and nothing warns you.
One file, several physical sizes
A design uploaded once is printed across a whole size run, and the artwork is scaled to suit each garment. That is convenient, and it quietly changes the arithmetic: a file sitting exactly at the density floor for the base print area falls below it on the larger sizes. The upload already succeeded, so nothing flags it.
The number that matters is a width, not a percentage
Scale factors are not published, so guessing at them is pointless. What can be stated exactly is the other direction: given a pixel count and a density floor, the widest print the file still satisfies. Divide the pixel width by the floor and you have it — 4500 pixels at 150 DPI holds up to 30 inches. Compare that to the base print area and you know how much room the size run has to eat.
Headroom against a 15″ base print area at 150 DPI
| 2250 × 2700 px | holds to 15″ — zero headroom, any upscale breaks it |
|---|---|
| 3000 × 3600 px | holds to 20″ — 33% headroom |
| 4500 × 5400 px | holds to 30″ — 100% headroom |
Where vector wins, and where it does not
A vector source has no fixed resolution, so you can export at whatever pixel dimensions the largest product needs and the question disappears. That is the real argument for keeping artwork in vector as long as possible — not that vector "looks better", but that it removes an entire class of failure from the workflow. Photographic and painted artwork cannot be vector, and for those the answer is simply to work at the master size from the start: you can always scale a large file down, and you can never recover what a small one never captured.
Frequently asked questions
Can I just upscale my file to get more headroom?
No. Upscaling adds pixels without adding information; the file passes the dimension check and still prints soft. If the pixels were never captured, they cannot be recovered — re-export from the source instead.
Does this apply to every platform?
Size-run scaling is documented for Printful. The general principle — build once at the largest size you will need and scale down — applies everywhere, because scaling down is lossless in the ways that matter and scaling up never is.