Half the artwork files we receive are not usable for printing, and the buyer only finds out after paying for samples. The fix is cheap and fast if you know the rules. This is the file checklist we send to every customer, with the numbers that actually matter for ceramic mug printing.
Resolution: 300 DPI at Final Print Size
Your logo needs to be 300 DPI at the exact size it will print on the mug, not at the size it appears in your email signature. A file that is 1,000px wide at 72 DPI looks fine on screen and becomes visibly soft when stretched around an 11oz mug. At 300 DPI, a full-wrap 11oz print area of about 90x210mm needs roughly 1,060×2,480px of actual pixel data. If your source is a screenshot or a logo pulled from a website, it will not survive; get the original vector file from your designer.
Bleed and Safe Zone: 3mm and 10%
Add 3mm of bleed on all sides of the print area so the design runs edge to edge without white slivers when the wrap is applied. Keep critical elements, especially text and logos, at least 10% inside the print boundary because the wrap shrinks slightly during heat application and the mug is a curved surface, not flat. Text closer than that gets cut or distorted at the edges. We reject files where the logo touches the bleed line, because there is no way to recover it in production.
Color Profiles: CMYK In, Expect a Shift
Send files in CMYK, not RGB, and know that ceramic printing shifts color versus a screen anyway. Sublimation inks and ceramic glazes do not hit the same gamut as a monitor; expect a visible shift, usually toward duller or darker tones. We proof against Pantone references and aim for ΔE under 3, which most people cannot perceive side by side. If your brand color is a bright neon or a deep saturated red, order a color sample before production because those two families shift the most.
File Formats: What We Accept and What We Reject
Preferred: AI, EPS, PDF, or high-res PNG with transparent background. Acceptable: SVG and 300 DPI TIFF. Reject outright: JPEG with a white background box (the white block prints around your logo), low-res PNG, and anything under 300 DPI. Transparent PNGs are the most common working format for single-color logos. For full-wrap photo designs, a layered PSD or a print PDF at 300 DPI is what we actually print from.
The Mistakes We See Every Week
Three errors dominate. First, tiny fonts: anything under about 4mm high on the mug becomes unreadable and looks like a smudge; we flag it before printing. Second, reversed-out text (white text on dark backgrounds) prints fine in sublimation but poorly in screen printing because each color is a separate screen and fine white lines misalign. Third, artwork designed for flat surfaces with a large border: borders wrap around the mug and the join line shows. Send a cylinder mockup if you are unsure; we will wrap your file around a mug shape and show you the result before you approve anything.
Send a File You Would Print on Paper
A print-ready file is 300 DPI at final size, CMYK, with 3mm bleed and a 10% safe zone, in a vector or high-res format. If your file fails any of those checks, fix it before you order samples, not after. Contact COMAIN CERAMIC and we will check your artwork file for free before you commit to anything.