How to Prepare Your Artwork for DTG T-Shirt Printing

20 April 2025 · 6 min read

Your design might look perfect on screen and come out muddy, washed-out, or blurry on fabric. Almost every failed print traces back to the same five file mistakes — and every one of them is preventable before you upload anything.

What DTG Printing Actually Does to Your File

Direct-to-garment (DTG) printing works like an inkjet printer — but instead of paper, it prints directly onto fabric fibres using water-based inks. The printer reads your file pixel by pixel and translates it into ink deposits on the shirt. This means the quality of your output is literally determined by the quality of your input file. There is no magic sharpening step on our end.

Printopia's T-shirts are printed on the Bella + Canvas 3001 — 100% ring-spun cotton, which accepts DTG ink extremely well. But the blank's quality only shows if your file gives the printer enough information to work with.

File Format: Always PNG

Use PNG with a transparent background for any design that isn't a solid rectangle. JPEG flattens your design onto a white background — so if your graphic has a shape, a JPEG will print a white box around it. PDF and PSD files are not accepted by most DTG workflows. PNG is the universal standard for a reason.

If your design is a full-bleed rectangular graphic (all four corners used), JPEG at maximum quality is acceptable. But when in doubt, export as PNG.

Resolution: 300 DPI at Print Size

This is where most designs fail. Screen resolution is 72–96 DPI. Print resolution needs to be at least 150 DPI, and ideally 300 DPI — at the actual size you want the design to print.

A common mistake: designing at 500 × 500 px and expecting it to fill a 30 cm print area. At that size, 500 px covers roughly 4 cm at 300 DPI — you'd get a small, pixelated stamp, not a full-chest graphic.

Colour Mode: RGB, Not CMYK

DTG printers are calibrated to work in RGB colour space. If you design in CMYK (common in print design software like InDesign), the colours can shift unpredictably when the printer converts them back to its internal RGB model. Design in RGB from the start, and what you see on screen will be much closer to what comes out on the shirt.

One important caveat: monitor brightness and shirt fabric texture both affect perceived colour. Dark shirts require a white underbase ink layer — this slightly mutes very vivid colours. If your design is going on a dark shirt, expect slightly less saturation than on a white or light-coloured shirt. This is a physical constraint of ink-on-fabric, not a printing error.

Dark Shirt Specifics: You Need Transparency

On dark shirts, the printer lays down a white ink underbase first, then prints your design on top. This only works if your file has a transparent background — the printer uses transparency to know exactly where to apply the underbase. If your file has a white background (even a "white" that looks like transparency in Photoshop but isn't), the printer will print a solid white rectangle behind your design.

What About Thin Lines and Small Text?

DTG printing can reproduce fine detail, but very thin lines (under 2 pixels at final print size) can break up or disappear. Small text below 8pt tends to blur. If your design has intricate line work, test by zooming your file to 100% and checking whether fine elements are still crisp — if they look fuzzy on screen at actual print size, they'll look worse on fabric.