How to Prep Artwork Files for Custom Printing: Vector Files, DPI & Colour Modes

You’ve got the design. You’ve chosen the garments. Now you send the artwork to your printer and get an email back asking for a vector file, higher resolution, or a different colour mode.

If you don’t work with design files every day, terms like vector, DPI, RGB, CMYK and Pantone can get confusing pretty quickly.

The good news is that you don’t need to be a graphic designer to supply print-ready artwork. Here’s what you need to know before sending your files for custom printing.

Vector vs Raster: What’s the Difference?

The first thing to understand is whether your artwork is vector or raster.

Vector Artwork

Vector graphics are built using mathematical paths rather than individual pixels. That means they can be scaled from a small chest logo to a large back print without becoming blurry or pixelated.

Common vector file formats include:

• AI: Adobe Illustrator
• EPS: Encapsulated PostScript
• SVG: Scalable Vector Graphics
• PDF: Can contain vector artwork, although not every PDF is automatically a vector file

Vector files are usually the preferred format for logos, text and illustrations used for screen printing and embroidery preparation.

Raster Artwork

Raster images are made from pixels. JPG, PNG and many Photoshop files are raster-based.

They can still produce excellent prints, particularly for photographic or highly detailed artwork, but the original file needs to be large enough for the intended print size.

If you take a small 500-pixel-wide logo from a website and stretch it across the back of a hoodie, those pixels have to stretch too. The result can be blurry edges and a noticeably lower-quality print.

What Does Vectorising Artwork Mean?

Vectorising means converting pixel-based artwork into clean, scalable vector paths.

This is particularly useful when you only have an old JPG or PNG of your logo but need to use it for professional printing.

However, simply opening a JPG in Illustrator and saving it as an AI or EPS file doesn't make it vector artwork. The design itself needs to be recreated or properly traced into vector paths.

For simple logos, this process is relatively straightforward. More complicated illustrations can require manual redraw work to maintain clean lines, accurate shapes and colours.

Melbourne Merch offers logo vectorisation and pre-press artwork preparation if your existing files aren't suitable for production, with simple vectorisation included on most orders and more complex redraws quoted separately.

What DPI Do You Need for Custom Printing?

DPI stands for dots per inch, although when discussing digital artwork you'll also commonly see PPI (pixels per inch).

For raster artwork, resolution matters.

As a general rule, 300 DPI at the final print size is a good target for high-quality garment printing.

The important part is at the final print size.

For example, an image might technically be labelled 300 DPI, but if it's only a few centimetres wide and needs to be enlarged to a 30 cm back print, the effective resolution will drop significantly.

Simply changing a low-resolution image from 72 DPI to 300 DPI in Photoshop doesn't magically add the missing detail either. The original artwork needs enough pixel information to support the required print dimensions.

Quick Rule

If you're supplying raster artwork:

Aim for 300 DPI at the actual size you want it printed.

Whenever possible, send the original artwork rather than an image downloaded from a website, screenshot or social media post.

RGB vs CMYK: Which Colour Mode Should You Use?

This is another common source of confusion.

RGB

RGB stands for Red, Green and Blue and is primarily used for digital screens, including phones, computers, TVs and websites.

Screens create colour using light, which means they can display some bright and vibrant colours that are difficult to reproduce physically with ink.

CMYK

CMYK stands for Cyan, Magenta, Yellow and Key (Black) and is commonly used in commercial printing.

Because printed colours are created with physical inks rather than light, a design can look slightly different when converted from RGB to CMYK.

This is why an extremely bright colour on your laptop may appear more muted once printed.

For some digital garment printing workflows, your printer may prefer to receive RGB artwork and handle the colour conversion through their own production software. Rather than converting everything yourself, check the artwork requirements for the specific printing method.

What About Pantone Colours?

If colour accuracy is particularly important, for example, you're printing a corporate logo that needs to match established brand guidelines, Pantone (PMS) colours can provide a more consistent colour reference.

Pantone assigns specific codes to colours, giving the printer a defined target rather than relying on how a colour appears on your screen.

This can be especially useful for screen printing, where inks can be mixed to closely match specified Pantone colours.

If your brand guidelines include Pantone references, include them when supplying your artwork.

Convert Fonts to Outlines

If your design contains text, the printer may not have the exact font you've used.

When a file is opened on another computer without that font installed, the software may substitute a completely different typeface.

The easiest way to prevent this is to convert your fonts to outlines before sending the final vector artwork.

Once outlined, the letters become vector shapes rather than editable text, meaning they'll appear exactly as intended regardless of which fonts are installed on the printer's computer.

Keep an editable copy of your original artwork before outlining the fonts, as outlined text is much harder to edit later.

Remove Backgrounds Where Required

If you're supplying a PNG or other raster artwork for DTF printing, make sure any background you don't want printed has actually been removed.

A white background on your screen isn't necessarily transparent.

This matters particularly when printing onto coloured or dark garments. If the artwork contains a white rectangular background, that rectangle may become part of the final print.

For raster artwork requiring transparency, a high-resolution PNG with a transparent background is generally preferable to a JPG, as JPG files don't support transparency.

Check Your Artwork at the Actual Print Size

Before sending the file, think about how large you actually want the design to appear on the garment.

A logo that looks perfectly proportioned on your laptop screen might feel completely different when printed 30 cm wide across a hoodie.

Consider:

• Final print width and height
• Front, back or sleeve placement
• Distance from the collar
• Whether the design is centred
• How the artwork will look across different garment sizes

Your printer can usually help with final positioning, but providing clear instructions reduces unnecessary back-and-forth during pre-production.

Artwork Checklist Before Sending It to Print

Before uploading your artwork, check:

• Vector where possible: AI, EPS, SVG or vector PDF
• Raster resolution: Ideally 300 DPI at final print size
• Fonts: Converted to outlines for vector artwork
• Background: Transparent where required
• Colours: Pantone references supplied if colour matching is important
• Artwork size: Appropriate for the intended print dimensions
• Original files: Avoid screenshots, social media downloads and compressed images where possible

Most importantly, don't upscale a poor-quality logo and assume it's now print-ready. If the source artwork isn't suitable, fixing it before production will usually give you a much cleaner result.

What If Your Artwork Isn't Print-Ready?

Don't panic if all you have is a JPG from an old website, a PNG from Canva or a logo that's too small for the print you want.

That's exactly what pre-press artwork preparation is for.

The Melbourne Merch team can check your files, identify potential production issues and prepare artwork for printing. For logos that need rebuilding, our vectorisation service can turn suitable raster artwork into clean, scalable files that can be used across future print projects too.

Whether you're preparing artwork for screen printing, DTF, embroidery or custom merchandise, getting the file right before production helps avoid delays and gives you a much better chance of getting the result you expected.

Get in touch with Melbourne Merch if you're unsure whether your artwork is ready to print. Send us what you've got, and we'll help work out what needs to happen next.