DTG print file checklist: resolution, transparency and color

Direct-to-garment (DTG) printers print straight from your file, like an inkjet printer for fabric. What is in the file is what lands on the shirt, including the mistakes you can't see on screen. Here are ten checks to run before you upload, with what Printful, Printify and Amazon Merch on Demand ask for. If you sell on Etsy through a print-on-demand service such as Printful or Printify, that service's file rules are the ones that apply.

1. The canvas matches the print area.

Make the file the size of the area it will print on, at 300 dpi. For a full front, that is usually 4500 × 5400 px, which is 15 × 18 inches: Printify and Amazon Merch both use it for a standard t-shirt. Printful's usual t-shirt area is 12 × 16 inches, or 3600 × 4800 px at 300 dpi, and 15 × 18 inches on select DTG products.

Your design can be smaller than the canvas. The rest of the canvas stays transparent.

2. The resolution is real, not relabeled.

Typing 300 into an image editor's resolution box changes a label, not the picture. Check the pixels: width in pixels divided by print width in inches should be 300, or at least 150, which Printful calls the sweet spot for its products. A 900 px wide file stretched to 15 inches is 60 dpi, whatever the label says.

3. The file is a PNG.

PNG keeps every pixel and can be transparent. JPG can't hold a transparent background, which is why Printful asks for a PNG whenever the background must not print, and why Amazon Merch takes PNG.

4. The background is transparent.

A white background is invisible on your screen and prints as a white box on a colored shirt. Open the file in an image editor: a transparent background shows as a gray and white checkerboard. Watch for the fake kind, a checkerboard drawn into the pixels of an image you downloaded somewhere. It prints as a checkerboard.

5. No soft glows, shadows or faded edges.

This is the check most sellers miss. DTG printers lay white ink under the colors on dark shirts, and, as Printify's guide explains, the printer treats any pixel that isn't fully transparent as a place for that white base. A soft glow, a feathered shadow or a layer at 30% opacity becomes a pale, chalky ring around the design.

The fix is to make every area either solid or fully transparent. Shading can stay, as a pattern of small solid dots instead of a fade.

6. Colors are in sRGB.

Printful asks for the sRGB IEC61966-2.1 profile and Printify for sRGB; seller guides say the same for Amazon Merch. Design in RGB, not CMYK. And expect fabric to print a little softer than your screen: a test shirt tells you more than any profile.

7. The file is under the upload limit.

Limits vary: Amazon Merch allows 25 MB per file according to seller guides, Printful's Design Maker accepts files up to 200 MB, and Printify's help center lists 100 MB for a PNG. A flat-color PNG is far under all three. The 4500 × 5400 print PNGs Optracy made for our 12 test designs weighed 0.4 to 3.3 MB each.

8. Thin lines and small text survive at print size.

View the file at 100% at its real print size. A hairline that is one or two pixels wide at 300 dpi is very thin on a shirt, and the fabric's texture can break it up. Small text with tight letter spacing can fill in. Thicken lines and open up small text before you upload, not after a buyer sends a photo.

9. No stray specks.

Scroll the edges of the design at 100%. Stray dots of color left by compression or by a rough background removal print as specks of ink. Remove them, or merge them into the color around them.

10. It looks right on the shirt color.

Preview the design on the shirt colors you will sell. Dark parts of a design vanish on a black shirt; light parts vanish on white. If a design sells in both, you may need two versions with different colors.

Where Optracy helps, and where it doesn't

For flat-color art, Optracy's print PNG takes care of checks 1, 3, 4, 5 and 7:

• It comes at 4500 × 5400, 4000 × 4000 or 3000 × 3600 px at 300 dpi, with your design at its proportions and a transparent margin.
• One button removes the background color, and the PNG is transparent there.
• Every color area is solid. The only partly transparent pixels are a one-pixel smoothing line along the outer edge of the design, 1/300 of an inch wide.
• Every file is checked before it reaches you: the size you chose, no trace of a hidden color, and no gaps in the print PNG.
• You can merge stray colors and recolor any group by its hex value, which helps with checks 9 and 10.

Where it doesn't help: photos and soft gradients, which become flat bands, so keep those as high-resolution PNGs. It doesn't make mockups or preview your design on a shirt photo. And it can't tell you how a color will look on fabric; only a test print can.

Sources

Platform facts checked on Oct 6, 2026. Platforms change their requirements, so check their own pages before you upload.

• Printify, PNG file setup for t-shirts and DPI for printing
• Printify help center, What type of print files does Printify require?
• Printful, Everything you need to know to prepare the perfect printfile and Create the perfect DTG file
• Printful's Etsy integration and Printify's How to dropship on Etsy
• Amazon Merch on Demand file requirements as summarized by Jungle Scout (2024) and Seller Sprite (2026)
• Optracy's own measurements of its print PNGs, Oct 6, 2026