CMYK vs Spot Colour Simulation

When it comes to printing full-colour or photographic artwork, there are two advanced screen printing methods we use at Print Room NZ: CMYK and Spot Colour Simulation. Here's how they differ — and when we recommend each.


CMYK Printing (Process Printing)

What it is: CMYK stands for Cyan, Magenta, Yellow, and Black (Key). These four transparent inks are printed in tiny overlapping dots to create the illusion of full-colour images — similar to how your home or office printer works.

Best for:

  • White t-shirts only

  • Photographic or detailed artwork with smooth gradients

  • Designs with lots of colours but no bright whites or bold solids

Limitations:

  • Can only be printed on white garments (the inks are transparent)

  • Colours may look slightly muted compared to spot colours

  • Not suitable for bold or flat graphic-style artwork


Spot Colour Simulation (Simulated Process)

What it is: Instead of using just 4 inks, simulated process uses custom-mixed spot colours to closely match the design. These are printed in specific layers to build up complex images, including gradients, bright colours, and dark fabric compatibility.

Best for:

  • Dark or coloured garments

  • Artwork that includes both photographic detail and bold graphics

  • Bright whites, neons, metallics, or high-impact prints

Limitations:

  • Requires more screens (usually 6–10+), so more complex to set up

  • Best suited to vector artwork or high-res separated files


Side-by-Side Comparison

Feature

CMYK Printing

Spot Colour Simulation

Ink Colours Used

4 (Cyan, Magenta, Yellow, Black)

6–10+ spot colours, mixed to match design

Garment Colour Compatibility

Only on white garments

Works on light and dark garments

Colour Accuracy

Good, but slightly muted

Excellent – bright whites and strong colours

Best For

Photos, smooth gradients on white tees

Bold + detailed art, high colour accuracy

Setup Complexity

Simpler setup

More screens and detailed separations required

Finish & Feel

Soft and smooth

Soft but slightly heavier with more ink coverage

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