Guide
DTF file requirements
The builder checks each file the moment you add it, so a problem shows up before you pack a layout, not after you order. These are the checks it runs, and what each one means for print quality.
File type
PNG and JPG are supported. A PNG with a transparent background is best: the builder trims the transparent edge to the visible artwork, so only the design itself takes up film. A JPG has no transparency, so the whole rectangle prints, including its background.
Resolution
A PNG can store its resolution in dots per inch (DPI). The builder reads it when present. Without a stated resolution, the design is assumed to print at 300 DPI, and you can also set its printed width directly.
The effective resolution is the pixel count divided by the printed size you have set. Below 250 DPI, the builder shows a warning next to that design, because print quality drops at low resolution.
Printed size
Each design prints at the size its resolution and pixel count give it, unless you set a width yourself. A design wider than the chosen printer's film, in both orientations, cannot be placed and is reported separately from the packed layout.
Where the check happens
Every check runs in your browser as the file is read. Nothing is uploaded to check a file, and closing the tab clears it.