CMYK vs RGB — Why It Matters for Plastic Card Printing

RGB is for screens. CMYK is for print. If you send RGB artwork to a card printer and nobody catches it, the colours that come back on your finished cards will be wrong — sometimes dramatically so.

That vivid neon blue on your monitor? It almost certainly cannot be reproduced in CMYK ink. You will get a duller, different shade. The sooner you convert your file to CMYK and proof it, the fewer surprises you get.

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What RGB actually is
RGB stands for Red, Green, Blue. It is an additive colour model — screens mix light to create colours, and combining all three at full intensity gives you white. It has a much wider colour gamut than print, meaning it can represent colours that physically cannot be reproduced with ink on a substrate.

What CMYK actually is
CMYK stands for Cyan, Magenta, Yellow, Key (Black). It is a subtractive model — ink absorbs light rather than emitting it. Mixing all four inks produces a dark brown-black in theory; that is why a separate black (K) ink exists for clean, dense text and solid dark areas.

Plastic card printers — whether offset litho or digital — print in CMYK. Your artwork needs to be in this mode before it goes on press.

What goes wrong with RGB files

- Colours shift on output, especially saturated blues, greens, and oranges
- The RIP (raster image processor) at the printer converts RGB to CMYK automatically — but it makes its own decisions about how to do that, not yours
- Brand colours can drift significantly. A Pantone-matched corporate blue can look purple or grey
- Some printers will flag the issue; others will just print it. Do not rely on them catching it

How to convert correctly

Adobe Illustrator or InDesign: go to Edit > Colour Settings, set your working CMYK profile (usually ISO Coated v2 or FOGRA39 for European print), then convert your document colour mode to CMYK.

Photoshop: Image > Mode > CMYK Colour. Do this before you start laying out artwork, not at the end — converting after the fact changes how every colour looks on screen.

Canva and similar browser tools: most do not give you true CMYK control. Export as a high-resolution PDF and check with your printer whether their workflow handles the conversion, or use a proper design tool.

Spot colours and Pantone
If brand colour accuracy is critical — a specific Pantone blue, an exact red — ask your card printer whether they can match Pantone references. Many digital card printers cannot; they print CMYK only. Offset litho printers can often add a spot colour at extra cost.

If you specify a Pantone colour, make sure your artwork uses the correct Pantone swatch, not just something that looks right on screen.

Ready to send your artwork?
Always supply artwork as a CMYK PDF with bleed. If you are unsure, ask your printer before you finalise the design — not after you have ordered 500 cards. We are happy to check your files before you commit.

View our plastic card printing options or contact us if you have a question about your artwork.