How to get a T-shirt design ready for screen printing

Screen printing is still the go-to for team shirts, band merch, events and bulk orders. The prints are bold, durable and cheap per shirt once you're printing more than a handful.

It's also the method that's pickiest about artwork, because every colour is printed through its own physical screen. A design that looks great on screen can be expensive, or impossible, to screen print as it is. Here's how to prepare it.

How screen printing works (in 30 seconds)

For each colour in your design, the printer makes a screen: a fine mesh with a stencil of just that colour's shapes. Ink is pushed through the mesh onto the shirt, one colour at a time, lined up precisely.

That explains almost every file requirement:

• Each colour costs a screen, so the number of colours affects price.
• Each colour must be a separate, clean shape, so the stencil can be made.
• Shapes must be solid. Ink is either there or not; there's no "50% transparent" ink.

1. Limit and define your colours (spot colours)

Screen printing uses spot colours: specific, pre-mixed inks. Instead of millions of colours blended on screen, your design needs a defined set of flat colours.

• Decide how many colours you need. One to four is common for most apparel orders.
• Make every area of the same colour exactly the same colour value, not dozens of near-identical shades.
• If brand colours matter, give your printer Pantone references. That's how inks are matched.

Remember the shirt colour is free: you can often use it as part of the design instead of printing it.

2. Separations: one layer per ink

Colour separation means splitting the design into one layer per ink, each becoming its own screen. Many printers do separations themselves, often for a fee, but a clean file makes it faster and cheaper, and avoids surprises.

For clean separations:

• Vector artwork is ideal. Each colour is already a distinct, clean-edged shape.
• No soft edges, glows or feathering unless they're converted to halftones (below).
• No tiny gaps between colours where the shirt would show through. Printers often add a slight overlap called trapping so colours meet cleanly.

3. Gradients, shadows and photos: use halftones

Ink can't be "half there," so gradients, shading and photographic detail are printed as halftones: patterns of solid dots that vary in size. From a normal viewing distance, the dots blend into a smooth fade.

Things to know:

• Halftones for apparel are usually coarser than in magazines, because fabric can't hold very fine dots.
• Very small dots can disappear or fill in, so extremely subtle gradients may print unevenly.
• Your printer will usually create halftones during separation, but it helps to know that soft effects will become dot patterns.

If you want a simple, bold print, flat colours without gradients are the safest choice.

4. Dark shirts need an underbase

Most screen printing inks are slightly translucent. On a black or navy shirt, colours printed directly look dull. So printers first lay down a white underbase, a layer of white under the colours, to make them pop.

This usually means one extra screen, which affects cost. Keep in mind:

• Fine detail has to line up across the underbase and the colour, so very thin lines are harder on dark shirts.
• A design built for white shirts may need adjusting for dark ones.

5. Thin lines and small text

Fine detail is limited by the mesh and the fabric. As a general guide:

• keep lines comfortably thicker than a hairline, around 1 point (about 0.35 mm) or more, and thicker on dark shirts
• avoid very small text, especially thin fonts and serifs
• avoid tiny isolated dots that can fall out of the stencil

Ask your printer about their minimums; they vary with equipment and fabric.

6. Size it for the print area

Common print widths, as a rough guide:

• Left chest: about 3.5 to 4 inches
• Full front, adult: about 10 to 12 inches
• Full back: about 12 to 14 inches
• Sleeve: about 3 inches

Many printers use the same screen for all shirt sizes in an order, so a 12-inch print on an adult small can look very different from one on an XXL. Check how your printer handles mixed sizes.

7. File format

The best file to send is vector: AI, EPS, PDF or SVG, with fonts converted to outlines. If you only have a raster file, send the largest, cleanest PNG you have, at least 300 pixels per inch at print size, with a transparent background.

Avoid JPGs where possible. Compression creates noise around edges that makes separations messy.

Screen printing prep checklist

1. Colours reduced to a defined set of flat spot colours
2. Pantone references for any brand colours
3. Gradients and shadows either removed or ready to become halftones
4. No thin hairlines, tiny text or isolated specks
5. Adjusted for dark shirts if needed (underbase planned)
6. Sized to the actual print area
7. Vector file with outlined fonts, or a large clean transparent PNG

Getting rejected or quoted extra for "art prep"? We fix the common problems (low resolution, fake transparency, too many colours, too-thin detail) and size and format your artwork for screen printing, DTF, DTG, sublimation or vinyl. You'll see the price before you pay.