Rule 1: transparent PNG, not JPG
The most important point first: your design sits on a colored surface — the fabric of the shirt, the ceramic of the mug. If your image has a white or colored background, it gets printed along with the design as a visible rectangle. Only a PNG with a transparent background lets the surface show through around the artwork. JPG can't do transparency and is therefore the wrong format. Why that is, is explained in the post Alpha channel and transparency.
Rule 2: high resolution — 300 dpi at print size
A textile print is viewed from up close, so no compromises on sharpness: 300 dpi at the actual print size. Rules of thumb:
- chest print 25 × 25 cm → approx. 2950 × 2950 px
- large back print 30 × 40 cm → approx. 3540 × 4720 px
- mug design 20 × 8 cm → approx. 2360 × 945 px
A logo saved from the web (often only a few hundred pixels) is never enough for this. Best of all is a vector design (SVG), which scales to any size without loss — then export a high-resolution transparent PNG from it.
Rule 3: the color shock
Colors on fabric are a world of their own. Two effects regularly catch people by surprise:
- The fabric color shows through. The same design looks completely different on a white, gray, and black shirt. Light colors on dark fabric often need a white underbase layer to really pop.
- Vivid colors get muted. As with CMYK printing, punchy on-screen neon colors can't be reproduced as brightly on fabric. If you need an exact color, clarify it with the provider.
Practical tip: check the design mentally (or in a preview) against the target fabric color, not just on a white screen.
What works well on fabric
Not every image is a good fit. These work best:
- graphics and lettering with clear shapes and solid areas;
- cut-out designs without a background;
- pared-down illustrations with few colors.
Photos with soft gradients and a full background often look busy on fabric — if you use a photo, cut it out and keep the main subject clear. Cutting out a subject is covered in the post Making an image background white (for printing, export it transparent instead of white).
The checklist before uploading
- Transparent PNG (not JPG)?
- 300 dpi at the actual print size?
- Design checked against the target fabric color?
- Clear shapes instead of a busy photo background?
- Provider's margin/position specs followed?
Frequently asked questions
What resolution does artwork for textile printing need?
300 dpi at the actual print size. A 25 × 25 cm chest print at 300 dpi comes to roughly 2950 × 2950 pixels. Since the design is viewed up close, don't cut corners here — blurry edges stand out immediately on fabric.
Why do I need a transparent PNG?
Because the design sits on a colored T-shirt: a white or colored background in the image would be printed along with it as a visible rectangle. Only a PNG with a transparent background lets the fabric show through around the design. JPG can't do transparency and is therefore unsuitable.
Why do the colors look different on the T-shirt?
Two reasons: textile printing works with a limited set of inks, and the fabric color shows through. A design on a black shirt looks different than on a white one. Vivid on-screen colors come out more muted, much like in CMYK printing. Mentally check important designs against the target fabric color beforehand.
Can I print a photo on a T-shirt?
Technically yes, but with care: photos with soft transitions and a full background often look busy on fabric. Graphics, lettering, and cut-out designs usually work better. If you use a photo, cut it out and keep the subject clear — don't print it as a full rectangle.
Sources
W3C — PNG specification (transparency) · International Color Consortium — color profiles.