Key takeaways

• Send vector files for logos; raster artwork needs 300 dpi at print size (150 dpi minimum).
• Use transparent backgrounds and 100% solid colours; soft shadows print as halos.
• Keep text at least 14pt and lines thick enough to print and bond.
• Screen colours (RGB) differ from printed colours (CMYK); approve a physical sample.
• Check print size and position on the smallest and largest sizes.

Introduction

Most problems with printed T-shirts start before a single drop of ink touches fabric. A logo downloaded from a website prints blurred. A design with a soft glow shows a white halo on a black shirt. Fine text fills in and becomes unreadable. A bright neon green from the screen arrives as a dull olive.

These problems are avoidable. Printers do not need designers to be technical experts, but they do need artwork that suits the print method, the garment and the size it will be printed at. This guide explains how to prepare artwork that prints sharply and feels good to wear, using practical guidance from print shops including the UK printer Teepig, and the experience of Dsigngo’s own design team.

Vector and raster: the two kinds of artwork

Vector files

Vector artwork is made of mathematical paths, not pixels. It can be scaled to any size without losing sharpness. Common formats are AI (Adobe Illustrator), EPS, PDF (when saved with vectors) and SVG.

Vector files are ideal for:

• Logos, text and graphic shapes.
• Screen printing, where each colour is separated onto its own screen.
• Embroidery digitising, where clear shapes help the digitiser plan stitches.
• Vinyl cutting, which needs clean paths for the plotter.

Raster files

Raster artwork is made of pixels. Photographs and painted illustrations are raster. Common formats are PNG, PSD (Photoshop), TIFF and JPG.

Raster files are fine for DTF, DTG and sublimation, as long as the resolution is high enough at print size. Teepig asks for PNG files where possible, with a transparent background and solid colours.

Which should you send?

Send the original source file whenever possible. For logos, that means the vector file from whoever designed the logo. If you only have a small JPG, a designer can redraw (vectorise) it. Dsigngo’s design team offers this service.

Resolution: the most common problem

For raster artwork, resolution is measured in dots per inch (dpi) or pixels per inch (ppi) at the final print size.

• Ideal: 300 dpi at print size.
• Minimum: 150 dpi at print size. Below this, prints look soft or pixelated.

Teepig gives a useful example: a print 24cm wide at 300 dpi needs an image around 2,800 pixels wide. Most images on websites are only 72 dpi and a few hundred pixels wide, which is why logos copied from websites usually print blurred.

How to check resolution

Divide the image width in pixels by the print width in inches. One inch is 2.54cm.

• An image 3,000 pixels wide printed 25cm (9.8 inches) wide gives about 306 dpi. That is excellent.
• An image 1,200 pixels wide printed at the same size gives about 122 dpi. That is too low.

Increasing the pixel size in software does not add real detail. It only enlarges the blur. If the original is too small, the artwork needs to be recreated or redrawn.

Transparency and backgrounds

Use transparent backgrounds

For DTF and DTG, the printer prints everything in the file, including any background. A white or coloured box around your design will appear on the shirt unless it is removed. Teepig removes simple white backgrounds automatically and free of charge, but charges for editing more complex backgrounds.

If your design needs white areas, tell the printer, because automatic background removal may delete them.

Avoid semi-transparency

Semi-transparent pixels are a major cause of poor digital prints. DTF prints a white base under the colours, so a pixel that is 50% transparent may print as a pale, muddy patch. Teepig advises making every colour 100% solid.

Effects that create semi-transparency include:

• Drop shadows.
• Outer glows.
• Smoke, fog and fade-outs.
• Soft brushes and feathered edges.
• Reduced layer opacity.

On a dark shirt, these soft edges can print as a harsh white halo. Replace them with solid shapes or ask the printer to convert gradients into halftone dots.

Halftones: how to print gradients softly

A halftone breaks a gradient or shaded image into tiny dots of different sizes and spacing. From a normal viewing distance, the eye blends the dots into smooth tones.

Halftones are used in screen printing to print photographs and gradients with a limited number of spot colours. In DTF printing, Teepig uses halftoning to reduce large solid areas of ink, letting the fabric show through. This gives a softer, more breathable print with less of the heavy, sheet-like feel that large DTF transfers can have.

When you design for print:

• Keep gradients simple, and expect them to be converted into dots.
• Avoid very subtle gradients in light colours, which can disappear.
• Use the garment colour as part of the design. For example, a dark shirt can show through a halftone to create shadow.

Colours

RGB and CMYK

Screens display colour with red, green and blue light (RGB). Printers use cyan, magenta, yellow and black inks (CMYK), plus white for textiles. Some RGB colours, especially neon greens, bright oranges and electric blues, cannot be reproduced exactly with CMYK inks. Teepig warns that very bright neon colours print more muted.

Spot colours

Screen printing uses spot colours: inks mixed to an exact colour. Specify colours with Pantone references, for example Pantone 286 C. For textile-dyed fabric colours, Pantone TCX references are used.

Garment colour

The garment is part of the design. Teepig suggests matching the canvas colour behind your design to the garment colour while designing. This helps you see how the design will really look, and avoids designs that rely on a white background. It also advises against large white areas on coloured garments. Use the shirt colour instead.

Number of colours

For screen printing, each colour adds a screen and cost. Simplifying a design from six colours to three often makes it bolder as well as cheaper. For digital printing, colour count does not affect cost.

Text and fonts

• Minimum size: Teepig recommends a minimum text size of 14pt for DTF. Thin parts of letters must be thick enough to print and bond.
• Thin fonts: hairline serifs and light weights often break up. Choose medium or bold weights for small text.
• Outlines: convert text to outlines (curves) in vector files, so the printer does not need your fonts.
• Reversed text: white text on a dark shirt needs extra thickness, because ink can spread slightly.
• Embroidery text: small text is especially difficult. Letters below about 5–6mm high often lose clarity in thread.

Lines and fine detail

Very thin lines cause problems in every method:

• Screen printing: very fine lines may not hold on the screen or may fill in.
• DTF: the glue needs enough surface to bond. Teepig advises avoiding very thin lines.
• Embroidery: fine lines turn into a single running stitch and lose definition.

As a rule of thumb, keep lines at least about 0.5mm wide at print size for printing, and thicker for embroidery. Bold, solid edges with strong contrast give the sharpest results.

Photographs

Photos can look stunning on T-shirts, but they need care:

• Use well-lit, sharp, high-contrast images.
• Avoid dark photos with unclear subjects, which print as muddy shapes.
• Remove or soften the background for a cleaner result.
• Photos print best on white or light garments, as Teepig notes.
• Consider a stylised treatment, such as a duotone, posterised or halftone effect, especially on dark shirts.

Print sizes and placement

Good placement makes a design look professional. Typical sizes for adult garments:

Placement tips:

• A full-front print usually starts about 7–10cm below the collar. Prints placed too low look like they are sliding off the shirt.
• Left chest logos are placed on the wearer’s left, centred roughly over the chest.
• Check designs on small and large sizes. A print that suits an XL may be too wide for an XS, so large orders sometimes need two print sizes.
• Teepig suggests leaving around 60% of the garment showing for comfort and durability. Full coverage prints need a heavier garment.

Preparing artwork for embroidery

Embroidery needs its own approach:

• Simplify: remove fine details, gradients and small text.
• Limit colours: most designs work best with four to six thread colours.
• Mind the size: a 9cm left chest logo has far less room for detail than a printed version.
• Provide vector artwork: clear shapes make digitising faster and more accurate.
• Consider the fabric: piqué polos and heavier fabrics hold detail better than thin jersey.

The digitiser converts the artwork into a stitch file. Always approve a stitched sample before bulk production, because thread texture changes how a design reads.

Designing for light and dark garments

The same design often needs two versions, one for light garments and one for dark garments.

• On light garments, dark ink colours stand out and white areas can simply be left unprinted. Photographs and fine detail look their best.
• On dark garments, colours need a white underbase to stay bright. White becomes an important ink colour, and outlines may need to be thicker so the design reads clearly against the dark fabric.
• Mid-tone garments such as grey, red and royal blue can be the hardest. Both dark and light ink colours may lose contrast. Test the design on the actual shirt colour.

If a design will appear on several shirt colours, ask your designer to prepare a version for each and to check the contrast. A black logo that looks crisp on white disappears on navy.

Mock-ups and the approval process

A mock-up is a digital image of your design placed on the correct garment, in the correct colour, at the correct size and position. It is the last chance to spot problems before anything is printed.

A good approval process has three steps:

1. Digital mock-up: check spelling, colours, size and position on the front, back and sleeves.
2. Physical sample: for bulk orders, a printed or embroidered sample on the real garment confirms colours, feel and durability.
3. Signed approval: a written approval of the sample and mock-up, which becomes the reference for production and quality checks.

Check spelling with special care. Names, dates, website addresses and phone numbers are where most errors hide. Ask someone who did not create the design to proofread it.

Sending files: naming and organisation

Clear files save time and prevent mistakes, especially for orders with several designs:

• Name each file clearly, for example “CompanyName_FrontPrint_Black_v3.ai”.
• Include a version number, and delete or archive old versions.
• Send one file per print position.
• Include a PDF mock-up showing all positions together.
• Package linked images and fonts with the design file, or convert text to outlines and embed images.
• For large files, use a file-sharing link rather than email attachments.

Personalisation: names and numbers

Team shirts and staff uniforms often carry individual names or numbers. To avoid errors:

• Supply the list in a spreadsheet with one row per shirt: name, number, size and colour.
• Check the spelling of every name with the wearer.
• Agree the font, size and position in advance.
• Decide how to handle long names, for example by reducing the font size or using initials.
• Keep the spreadsheet as the production reference, so every shirt can be checked against it before packing.

Common artwork mistakes

The same few mistakes appear again and again in artwork sent to printers:

• Logos copied from websites or social media, which are too small and print blurred.
• Designs on a white box, which prints as a white rectangle on a coloured shirt.
• Soft shadows and glows, which print as halos.
• Text too small or too thin, which breaks up or fills in.
• Neon colours chosen on screen, which print duller than expected.
• Prints too large for small sizes, which wrap around the sides of the shirt.
• Spelling errors, which are expensive to fix after printing.

Each of these can be caught by a designer in minutes, before production begins.

Artwork checklist

Before sending artwork to a printer, check that:

1. The file is vector, or a raster file at 300 dpi at print size.
2. The background is transparent, unless a background is part of the design.
3. All colours are 100% solid, with no soft shadows, glows or fades.
4. Brand colours are specified as Pantone references.
5. Text is at least 14pt and converted to outlines.
6. Lines are thick enough to print.
7. Print size and position are stated for each location.
8. A mock-up shows the design on the correct garment colour.
9. Any personalisation (names and numbers) is supplied in a clear spreadsheet.
10. Copyright and trade mark permissions are in place.

Copyright and trade marks

Only print artwork you own or have permission to use. Printing a sports club crest, a cartoon character, a famous logo or a photographer’s image without permission can infringe copyright or trade mark rights. Responsible printers will ask about ownership and may refuse artwork that appears to infringe. Fonts can also have licence restrictions for commercial use.

If you need original artwork, a professional designer can create it from your idea, so that you own the rights.

An example in practice

The following example is illustrative and does not describe a real client.

A Negombo surf school sends a 600-pixel JPG of its logo, copied from its website, for 150 shirts. At 25cm wide, the file would print at about 61 dpi. Dsigngo’s design team redraws the logo as a vector file, matches the turquoise to a Pantone reference, and removes the soft drop shadow, which would have printed as a grey halo on navy shirts. The final design uses three spot colours for screen printing, with the navy shirt colour used inside the wave shape instead of a fourth ink. The result is sharper and costs less.

How Dsigngo Group helps

Dsigngo started as a creative design agency in 2011, so artwork is where our apparel service begins. Our designers can create original T-shirt designs, redraw and clean up logos, separate colours for screen printing, prepare DTF files with halftones, create embroidery-ready artwork and produce mock-ups on the correct garments before you approve.

Frequently asked questions

Can I just send a JPG?

Yes, if it is large enough: at least 150 dpi, ideally 300 dpi, at print size. Logos are better as vector files.

Why does my design look different on the shirt?

Screens display RGB light, while printers use CMYK ink on textured fabric. Bright colours and gradients change most. Approve a sample for critical colours.

Can you remove a background for me?

Yes. Simple backgrounds are easy to remove. Complex photo backgrounds take more design time.

What size should my logo be on the chest?

Usually 8–10cm wide for adults.

Can I use any font?

Check the font licence for commercial use, choose weights that are thick enough, and convert text to outlines.

Conclusion

Good T-shirt printing begins with good artwork. Use vector files or high-resolution images, keep colours solid, avoid soft effects, size text and lines for print, and plan placement on every size. Most of all, approve a sample. A few minutes of preparation saves the cost and disappointment of a reprint.

Need help preparing your design? Send it to Dsigngo Group for a free artwork check.

Send Your Artwork

Related reading

• Custom T-Shirt Manufacturing: A Complete Guide from Idea to Delivery
• T-Shirt Fabrics Explained: Cotton Types, GSM, Blends and Organic Cotton
• Screen Printing, DTF, DTG, Embroidery and More: T-Shirt Decoration Methods Compared
• T-Shirt Fits and Sizing: How to Get the Size Right and Keep It That Way
• Corporate, Event and Team T-Shirts and Polos: A Buyer's Guide to Bulk Orders
• How Denim Jeans Are Made: From Cotton Field to Finished Pair

Sources

• Teepig, design guidelines: https://www.teepig.co.uk/help/design-guidelines/
• Teepig, halftone for DTF printing: https://www.teepig.co.uk/halftone-for-the-perfect-dtf-print/
• Teepig, quick tips: https://www.teepig.co.uk/help/quick-tips/