Preparing Vector Artwork for Screen Printing T-Shirts
Screen printers ask for vector files for a reason. Learn how color separations work, why fewer colors save money, how to handle gradients, line thickness and dark shirts, and what file to send your printer.
Screen printing is still the most popular way to print t-shirts in quantity: the colors are bright, the print lasts through hundreds of washes and the price per shirt drops as the order grows. But screen printing has its own rules, and the artwork you send has a big effect on both the quality and the price. This guide explains what your printer needs and how to prepare a vector file that prints well.
How screen printing works
In screen printing, each color is printed through its own screen — a fine mesh with a stencil of the design. Ink is pushed through the open areas of the mesh onto the shirt, one color at a time. A three-color design needs three screens, three setups and three passes.
That has two consequences:
- every color in the design must be a separate, solid shape (a "separation");
- each extra color costs money, because it adds a screen and setup work.
Why printers ask for vector files
Screens are made from film or digital output at the final print size. With a vector file the printer can scale the design to fit the shirt, separate the colors cleanly and output each screen with perfectly sharp edges. A small or blurry raster image has to be redrawn first, which often costs extra and delays the order.
Keep the color count low
Look at your design and count the colors you truly need. Many great shirt designs use only one to three ink colors.
- Merge colors that look almost the same. Two slightly different reds will become two screens.
- Ask whether the shirt color can be part of the design — leaving areas unprinted lets the fabric show through as an extra "color" for free.
- When you vectorize artwork, set a fixed number of colors instead of keeping every shade. In Vectorizo, the Colors option lets you choose 8, 16 or fewer, and similar shades are merged the way the eye groups them.
Use spot colors
Screen printers mix inks to match spot colors, usually from the Pantone system. If your brand has exact colors, tell the printer the Pantone codes rather than relying on how the colors look on your screen, because monitors vary. In your file, make each color a solid fill with no transparency.
Gradients and shading
Ink is either there or not, so a smooth gradient cannot be printed directly. Printers have three ways around this:
- simplify the shading into a few flat bands of color;
- use halftones, patterns of tiny dots that create the look of shading with one ink;
- use a different method, such as DTG (direct to garment) or DTF (direct to film) printing, which handles full-color images well.
For classic screen printing, flat-color artwork prints best and costs least.
Line thickness and small details
Very thin lines and tiny text can fill in or disappear, because ink spreads slightly into the fabric. As a rough guide, avoid lines thinner than about half a point (around 0.2 mm) and very small text, especially in white ink on a dark shirt. When you shrink a design to fit a pocket print, check that the details still survive.
Printing on dark shirts
On dark garments, colors are usually printed on top of a white underbase so they stay bright. The printer creates the underbase from your artwork, but it is one more screen, and very fine details are harder to register. Designs with bold shapes work best on dark shirts.
Size and placement
Create or check the artwork at the size it will be printed. Common front prints are roughly 10 to 12 inches wide for adult shirts, and a left-chest print is typically around 3 to 4 inches. Your printer will tell you their maximum print area. Because the file is vector, it can be scaled to any size without losing quality — but make sure details still read at the final size.
Prepare the file
Before sending artwork:
- Convert all text to outlines (paths), so the printer does not need your fonts.
- Remove the background unless it is meant to be printed.
- Delete hidden layers, stray points and unused colors.
- Check for tiny specks of color left over from tracing; each one would print.
- Make sure colors are solid fills, with no transparency, shadows or glow effects.
- Label the Pantone or ink colors if you know them.
What file format to send
Most screen printers accept AI, EPS, PDF or SVG. Ask what they prefer; many will happily take an SVG or PDF. Our vector file formats guide explains the differences.
From a pixel design to print-ready vector
If your design is a PNG or JPG — for example a sketch, an AI-generated image or an old logo — vectorize it first:
- Start from the largest, sharpest version you have.
- Convert it with an image vectorizer and choose a small number of colors.
- Set the background to transparent.
- Zoom in to check the edges and look for specks.
- Open the SVG in a vector editor to make final changes and convert any text to paths.
Summary
Screen printing rewards simple artwork: few solid colors, no gradients, lines that are not too thin and a clean vector file at the right size. Prepare your design with those rules in mind and you will get sharper prints, fewer surprises and a lower price per shirt.