File Formats: Vector vs. Raster

There are two types of image files used in artwork preparation: vector and raster. Choosing the correct one for your artwork type is the single most important decision you make before designing.

Why Vector Is the Preferred Format

Vector files use mathematical paths rather than pixels. This means a logo designed at 5cm can be output at 50cm without any loss of sharpness. For screen printing in particular, vector artwork is far easier to colour-separate and produces cleaner results at any print size.

If you don't have access to Adobe Illustrator, Canva offers a free web-based option for creating simple vector designs. CorelDRAW is another capable alternative.

When to Use a Raster File

Raster files are the correct choice for photographs, artwork with gradients, or any design where complexity makes vector impractical. The critical requirement is resolution: your raster file must be set to 300ppi at actual print size before you start designing — not resized up afterwards.

Accepted File Types at a Glance

Resolution & File Size

Resolution refers to the number of pixels packed into each inch of your image. For t-shirt printing, the human eye can no longer distinguish individual pixels at 300ppi, which is why this is the industry standard. Below 150ppi, pixelation becomes visible in the final print.

Setting Up Your Template (Before You Start Designing)

Resolution must be set before you begin designing — not after. Here are the recommended template settings:

Example — Adobe Photoshop: New Document Setup

Adobe Photoshop is the leading app for creating and editing raster artwork files. The example above shows the optimum settings to create a new document for a full-size chest or back print — 35cm wide × 40cm high at 300ppi.

Example — Adobe Illustrator: New Document Setup

Adobe Illustrator is the leading app for creating and editing vector artwork files. The example above shows the optimum settings to create a new document for a full-size chest or back print — 35cm wide × 40cm high. No resolution setting is required for vector files as they scale without any quality loss.

What If My Image File Is Too Small?

If you only have a small or low-resolution file, your options in order of preference are:

• 1. Locate the original source file or request a high-resolution version from the designer
• 2. Have the artwork recreated as a vector file by a graphic artist
• 3. Search for a larger version of the image online
• 4. Reduce the intended print size to match the resolution you have

Colour Modes: RGB vs. CMYK

Colour mode determines how colours are stored in your file. The two main modes are RGB (screen-based) and CMYK (print-based). For t-shirt and merchandise printing, save your artwork in RGB.

Critical Colour Matching: The Pantone Matching System (PMS)

If your brand colour must be reproduced accurately and consistently — across garments, print runs, and suppliers — use a Pantone (PMS) colour code. Pantone is an internationally standardised colour system where each colour is assigned a unique number, published in physical swatch books and recognised globally.

Quote your Pantone code when placing your order. The accuracy of the match depends on the print process:

• Screen printing: Very close Pantone match achievable
• Embroidery: Limited to the closest available thread colour
• DTG / DTF digital printing: Dependent on machine software interpretation

Design Tips for Print-Ready Artwork

1. Convert All Fonts to Outlines

This is a critical step. If a font used in your artwork is not installed on the system opening your file, the software will substitute a different font — changing the look of your design.

Converting text to outlines transforms it into a vector shape, eliminating any dependency on installed fonts.

2. Remove the Background — Use Transparent

Your design file must have a transparent background, not white. A white background will print as a solid white rectangle around your design on the garment — a common and avoidable mistake.

To remove a background in Photoshop, use the Magic Wand tool, Quick Selection tool, Background Eraser, or Masks. Ensure the edges of your design are clean and smooth. Export as PNG with transparency enabled.

3. Crop to the Outer Limits of Your Design

Trim the canvas so it sits just outside the edges of your artwork. Dead space around the design affects how the Design Tool positions and scales your file. In Photoshop, press C for the crop tool, or go to Image › Trim Transparent Pixels.

4. Stroke Line Thickness

Lines in your vector design should be at least 1pt thick to remain readable when printed. For reversed-out areas (fine detail that will be surrounded by ink), use a minimum of 2pt to prevent ink filling in during printing.

After finalising your design, expand all strokes in Illustrator (Object › Expand) to convert them into filled shapes. This prevents distortion if the file is resized during production.

5. Avoid Copyright-Protected Images

Do not use copyrighted images, logos, or brand assets without explicit permission. This includes sports team branding, band logos, movie characters, and photography from the internet. Copyright-free image sources include Unsplash, Pixabay, and Pexels. Alternatively, create original artwork or commission a designer.

6. Dark Garments — The White Underbase

When screen printing onto mid or dark coloured garments, a white ink layer is printed and flash-dried first before coloured inks are applied. Without this underbase, colours appear dull or distorted against dark fabric. 24 Hour Merchandise handles this process — you do not need to include a white underbase in your artwork file.

Printing & Embroidery Techniques Explained

24 Hour Merchandise offers three printing methods and embroidery. Each has different strengths, minimums, and artwork requirements.