RGB vs CMYK Printing: Why Screen Colours Can Print Differently

01What is the practical difference between RGB and CMYK?

RGB devices add coloured light. With more light, the display moves towards white; a modern screen can show bright blues, greens and other saturated colours that attract attention online. Its appearance still changes with brightness, display quality, calibration and room lighting.

CMYK printing places coloured inks or toners on a physical surface. The achievable range depends on the press or printer, ink set, paper or vinyl, profile, finishing and viewing light. A coated sheet and an uncoated sheet can make the same artwork feel different because the surfaces handle colour and contrast differently.

This is why use CMYK is not a complete production instruction. A colour space without the intended output condition or profile leaves important information unresolved.

02Should artwork always be converted to CMYK before sending it?

Not always. Some printers ask for a particular CMYK profile or PDF preset. Other production systems accept RGB elements and perform a controlled conversion for the selected device and material. Converting too early with a guessed profile can discard colour information or create a second conversion later.

Ask the supplier what to send for that product. Keep the original editable RGB artwork, linked images and brand references. Then prepare the delivery file according to the confirmed workflow. If the file is already CMYK, identify the embedded profile instead of assuming every CMYK file describes colour the same way.

03Which colours usually need the closest attention?

Very bright cyan, green, blue, purple and fluorescent-looking screen colours often deserve an early check. Deep shadows can also lose separation, while neutral greys may pick up an unwanted colour cast if the conversion or print condition changes.

Do not fix this by typing arbitrary CMYK percentages from an online converter. Ask whether the converted colour still performs its job: Is the logo recognisable? Is small text readable? Are two chart categories still distinct? Does a warning panel retain enough contrast?

If one brand colour is critical, provide its documented reference and explain where it matters most. The printer can then advise on the practical proof or production route for that job. No uncontrolled laptop or phone screen can guarantee an exact printed match.

04How should you preview a screen design for print?

Use colour-managed software and the output profile requested for the job. A soft proof can simulate the expected print condition on a calibrated display and can flag colours outside that output gamut. It is a preview, not the printed object: screen calibration, paper colour, texture, ink and viewing light still matter.

For colour-sensitive work, ask what proof options are appropriate. A digital PDF proof is useful for wording, position and page order, but it may not prove final colour. A physical or contract proof may provide better colour evidence, although its purpose, cost and relationship to the production device must be confirmed in the quotation.

05Worked example: a brochure and banner use the same brand colours

Imagine one design uses a vivid cyan headline, orange button and dark photograph. It will become an A4 brochure and a large banner.

The aim is not to make two unlike materials behave identically. It is to preserve the intended hierarchy and achieve an acceptable, agreed result for each product.

• Keep the editable master and original photograph.
• Record the approved brand references and identify cyan as the highest-priority colour.
• Ask for the brochure and banner colour and profile requirements separately because paper and banner material use different output conditions.
• Convert or export each delivery file using the confirmed instruction; do not reuse one guessed conversion for both.
• Soft-proof the cyan, orange, skin tones and shadow detail.
• Request the proof route appropriate to each item, then approve content and colour expectations separately.

06A copy-and-send colour and artwork brief

Send enough information for the printer to confirm the correct file, conversion and proof route before production. Scope, price, timing, revisions and proof arrangements remain specific to the individual job.

• Product and finished size: item, width x height.
• Quantity and material, if known.
• Supplied file: AI, PDF or other, with RGB, CMYK or unknown profile.
• Brand colour reference and the colour-critical area.
• Previous printed reference: available or not available.
• Required date and postcode for job-specific confirmation.
• Ask the printer to confirm the colour space, profile, export preset and proof route.