What is CMYK and RGB?
– and why are they different in the Print space?
CMYK and RGB both refer to colour spaces (or colour models), but they are used for very different purposes. Understanding the difference is essential if you want your printed material to look the way you expect it to.
What Do CMYK and RGB Stand For?
RGB stands for Red, Green, and Blue. It is a colour model used for devices that emit light, such as computer screens, smartphones, televisions, and tablets. By combining red, green, and blue light at varying intensities, RGB can produce trillions of colours, resulting in bright, vibrant, high-definition visuals. This gives RGB a much wider colour gamut than CMYK.
CMYK stands for Cyan, Magenta, Yellow, and Black (Key). It is the colour model used in physical printing. Unlike screens, printed ink does not emit light—it absorbs light as it is printed onto a substrate such as paper, board, or other materials. Because of this, printed colours are naturally more muted than what you see on a screen.
Where Are RGB and CMYK Colour Spaces Used?
RGB is used for:
- Smartphones and tablets
- Computer monitors and laptops
- Televisions and digital displays
Each pixel on a screen is made up of three smaller subpixels—red, green, and blue—which emit light to create colour.
CMYK is used for:
- Flyers and Brochures
- Books, Manuals, and Magazines
- Catalogues
- Paper-based Carton and Box packaging
- Other printed products
Litho, Toner, and Inkjet Presses reproduce colour by printing layers of CMYK ink in varying dot sizes and densities on a sheet of paper or board. Because paper absorbs light rather than emitting it, printed colour will always appear different from what you see on a screen.
This is why a design that looks perfect on your computer may not look identical once printed.
Designing on Screen vs Printing on Paper
When you design on a screen, you are viewing colour through RGB light, not printed ink. Screens can appear brighter or darker depending on:
- Ambient lighting in the room
- Screen brightness settings and screen calibrations
For this reason, screens should be treated as a guide only, not a definitive reference. Professional designers and printers rely on certified printed colour guides and calibrated workflows to ensure accurate results.
What Happens to an RGB File in a CMYK Print Environment?
In a professional print workflow, files are processed through systems that prepare them for the specific press being used. Ideally, designers should convert all artwork to CMYK within their design software before supplying files.
If RGB elements remain in the file:
- The print workflow or press will automatically convert them to CMYK
- Different workflows and presses use different conversion profiles, which can lead to inconsistent results
- RGB colours are converted to the closest available CMYK match, which often results in colours appearing duller or more muted
This is why unmanaged RGB-to-CMYK conversions can lead to unexpected outcomes.
In Summary
- Always ensure all files are supplied in CMYK, with no RGB elements remaining
- Never rely on your screen for accurate colour—screens emit light, while paper absorbs it
- Expect printed colours to appear more muted than on-screen versions
- When in doubt, ask for guidance and request a hardcopy proof before full production
Your Reliable Trustworthy South African Print Partner
At Remata Communications and Printers, we are proud to partner with a diverse range of clients – agencies, brokers, corporates and designers and trusted by organisations such as Wits, ABB, Ford, Vodacom, Isuzu, Exclusive Books, Agrinet, Rhodes University and Sun International. Its clear why Remata is regarded as a trusted commercial printing and packaging partner—delivering reliability, quality, affordability and partnership across every project.
Our experienced and knowledgeable team is ready to assist with your next print or packaging requirement.
Call us on 011 848 0000
Email [email protected]
Visit and browse our website and online store at www.remata.co.za