Resolution: What 300 DPI Actually Means for a Chest Print
By The Velocity Wear Team
Resolution confuses people because DPI on its own means nothing. A file is not "300 DPI" in the abstract — it has a pixel count, and the DPI is what you get when you divide those pixels by the physical size you print them at. The same file is 300 DPI at one size and 75 DPI at four times that size, which is exactly how a logo that looked fine becomes a soft print.
The arithmetic, once
Pixels divided by inches gives DPI. So a design 3000 pixels wide, printed 10 inches wide, is 300 DPI. Printed 20 inches wide, the same file is 150 DPI.
Run it the other way to check what you need. A full front print around 30cm — roughly 12 inches — at 300 DPI wants about 3600 pixels across. A left chest at 8cm, a bit over 3 inches, wants around 950 pixels.
That is the whole calculation, and doing it once before sending artwork prevents the most common file rejection there is.
Enlarging does not add information
Increasing the DPI setting in an image editor without changing the pixel count changes a label, not the file. Actually resampling upward invents pixels by interpolation, which produces a larger, softer image rather than a sharper one.
Modern upscaling tools are better than they used to be and can help with photographic content. They do not rescue a logo — for line art and type the correct answer is always to go back to vector.
What DTF specifically wants
- Final print size, at 300 DPI or better. Send the file at the dimensions it will actually be printed rather than leaving the scaling to be inferred.
- A transparent background where the design is not a solid rectangle. A white background in the file becomes a white rectangle on the garment.
- Clean edges. Soft or feathered edges from a poor cut-out print as visible fuzz, and heavy JPEG compression artefacts around a logo will reproduce.
- RGB or CMYK is generally workable, but flag which you are sending and give Pantone references for any colour that has to match exactly.
- No embedded low-resolution placed images inside an otherwise high-resolution file, which is a common and easily missed problem.
How to check a file quickly
Open it and look at the pixel dimensions, not the DPI field. Divide the width in pixels by the print width in inches. If the answer is 300 or more, you are fine. If it is under about 150, expect a visibly soft result.
The other quick test: view the file at 100% zoom, which shows one screen pixel per image pixel. If it looks soft at 100%, it will look soft printed, because you are already looking at the real information in the file.
Detail that disappears on fabric
Resolution is necessary and not sufficient. Fabric texture limits how fine a detail can reproduce regardless of how good the file is — a hairline that renders perfectly at 600 DPI can still vanish into the weave of an open knit.
Heavier, denser, smoother fabric holds finer detail. If your artwork depends on small type or thin lines, that is a reason to choose a tighter combed cotton over a coarse open one, and it is a conversation to have alongside the artwork rather than after the sample.
When in doubt, send the source
If you have the original layered or vector file, send it along with the flattened one. It costs nothing, and it means a resolution problem can often be solved by re-exporting rather than by asking you to find a designer.
