CMYK vs RGB: What's the Difference, and Which Should You Use for Printing?
If you’ve ever designed something that looked perfect on screen but came back from the printer looking duller or darker, the reason is almost always the colour mode. RGB is for screens. CMYK is for print. Anything you plan to have printed should be set to CMYK before it’s sent, because RGB files can shift colour once they hit the press.
Quick answer: CMYK is a four-ink colour system (cyan, magenta, yellow and black) used for printing. RGB is a light-based colour system (red, green and blue) used for screens. If your design is going to be printed, set it to CMYK. If it’s staying on a screen, keep it in RGB.
What is the difference between CMYK and RGB?
The difference is how each one creates colour. RGB builds colour from light, so it’s used for screens and can display very bright, vivid shades. CMYK builds colour from ink, so it’s used for print and works within the range of colours that ink can physically reproduce. Screens glow; paper doesn’t, which is why the two systems don’t match exactly.
| RGB | CMYK | |
|---|---|---|
| Stands for | Red, Green, Blue | Cyan, Magenta, Yellow, Key (black) |
| Creates colour with | Light | Ink |
| Best for | Screens, web, social media | Anything printed |
| Colour range (gamut) | Wider and brighter | Slightly narrower |
| Use it when | Your design stays digital | Your design is going to print |
What is RGB?
RGB stands for Red, Green and Blue. It’s the colour system every screen uses, from your phone to your laptop to a shop display. Screens create colour with light, mixing red, green and blue at different strengths. Add all three at full strength and you get white; turn them all off and you get black. Because it’s built from light, RGB can produce very bright, vivid colours, which is why images look so punchy on a monitor.
RGB is the right choice for anything that stays on a screen: websites, social media posts, email graphics and digital presentations. Hex codes (like #1A73E8) are RGB values too, which is why they belong to web design rather than print.
What is CMYK?
CMYK stands for Cyan, Magenta, Yellow and Key, and Key means black. It’s the colour system printers use. Instead of light, print creates colour with ink, layering those four colours onto paper in tiny dots to build every shade you see. Because it’s built from ink rather than light, CMYK can’t quite reach the same brightness as a glowing screen, but it’s what physically goes onto the page.
CMYK is the right choice for anything printed: business cards, flyers, leaflets, posters, booklets and banners. When you order print from us, CMYK is the mode we’re working in.
Why does this matter when you print?
Every colour system can only reproduce a certain range of colours, and that range is called the gamut. RGB has a wider gamut than CMYK, which means screens can display some colours that ink simply can’t reproduce. A bright electric blue or a neon green looks stunning on a monitor because the screen is emitting light, but there’s no ink combination that matches it exactly.
When an RGB file is prepared for print, those out-of-gamut colours are converted to the closest CMYK version available, and that version often looks flatter or darker than the original. A common example is a logo built around a vivid blue. On screen it glows; printed from an unconverted RGB file, it can come back looking closer to a muted navy or even slightly purple. Nothing has gone wrong with the printing. The colour was simply never one that ink could hit. This is the single most common reason a printed piece doesn’t match what someone saw on screen.
What happens if you send an RGB file to a printer?
In most cases the file will still print, because print software will convert it to CMYK automatically. The problem is that the conversion happens without you seeing it, so the colour shift comes as a surprise when the job is finished rather than something you had a chance to adjust. Setting your file to CMYK yourself puts that control back in your hands, lets you check the colours before you commit, and means there are no surprises when you collect the job.
How to set your artwork to CMYK
If you’re working in professional design software such as Adobe Illustrator, InDesign, Photoshop or Affinity, set the document colour mode to CMYK before you start designing, then export a print-ready PDF when you’re done. Setting it at the start is better than converting at the end, because you’ll be choosing your colours within the printable range from the outset. In Canva, the CMYK export option is available on the Pro plan when you download as a PDF for print.
When you export, it helps to use the right CMYK profile for where the job is printed. In the UK and Europe, a common one is FOGRA39; in the US it’s usually US Web Coated (SWOP). If you’re not sure, that’s fine, because it’s exactly the kind of thing we can check for you.
It’s worth checking two other things at the same time. Your images should be at least 300 dpi so they print sharply rather than blurry, and your design should include a small bleed area, usually 3mm, so there are no thin white edges after trimming. Colour mode, resolution and bleed are the three things that most often catch people out, and all three are quick to fix before a file is sent rather than after it’s printed.
A few print colour terms worth knowing
If you’re getting to grips with print for the first time, these are the terms that come up most often.
| Term | What it means |
|---|---|
| Colour gamut | The full range of colours a system can reproduce. RGB’s is wider than CMYK’s. |
| Colour profile | The specific setting that defines how colours convert, such as sRGB for screens or FOGRA39 for European print. |
| Spot colour (Pantone) | A pre-mixed ink matched to a fixed reference, used when a colour must be identical on every run. |
| Rich black | A deeper black made by adding cyan, magenta and yellow under the black ink, rather than black alone. |
| Bleed | A small margin (usually 3mm) extended beyond the trim edge so there are no white lines after cutting. |
| DPI | Dots per inch, a measure of image resolution. Print needs at least 300 dpi to look sharp. |
What about brand colours and Pantone?
If your brand relies on one exact colour that has to be consistent every single time, such as a specific corporate blue, it’s worth knowing about Pantone, also called spot colour. Pantone colours are pre-mixed inks matched to a fixed reference, so they print identically on every run rather than being built from the four CMYK inks. Not every job needs it, and standard CMYK printing is perfectly accurate for the vast majority of business print, but if colour consistency is critical to your brand it’s worth mentioning when you place your order so we can advise on the best approach.
Not sure if your file is right? We'll check it for you
Getting the colour mode right is exactly the kind of detail that’s easy to miss and frustrating to discover after a job has printed. If you’re unsure whether your artwork is print-ready, you don’t have to work it out alone. At Express Copy in Coulsdon we check the colour mode, resolution and bleed on every file before we print, so you know it’ll come out the way you intended.
You can upload your artwork to us and we’ll take a look, or see the full range of what we produce on our printing page. If you’d rather talk it through, call us on 020 8668 9799 or pop into the shop on Chipstead Valley Road.
Frequently asked questions
Should I use CMYK or RGB for printing?
Use CMYK. RGB is designed for screens, while CMYK is the ink-based system printers use, so CMYK gives you a far more accurate idea of how your printed piece will actually look.
Is CMYK or RGB better for printing?
CMYK is better for printing, without exception. RGB is only better for screens. The two aren’t competing; they’re built for different jobs, and print is CMYK’s job.
Can I convert an RGB file to CMYK?
Yes. Every professional design program lets you switch a document to CMYK, and Canva Pro exports a CMYK PDF for print. Do expect some of the brightest colours to shift slightly during conversion. That’s normal, and it simply reflects what ink can reproduce.
Do I need to convert my logo to CMYK before printing it?
Yes. If your logo is going onto anything printed, convert it to CMYK first so you can see how the colours will actually look, rather than leaving the conversion to chance during printing.
What is colour gamut?
Colour gamut is the full range of colours a system can reproduce. RGB has a wider gamut than CMYK, which is why some bright screen colours can’t be matched exactly in print.
Why do my printed colours look different from my screen?
Because your screen shows colour using light (RGB) and print uses ink (CMYK). Light can produce brighter, more vivid colours than ink, so very bright shades are toned down when they’re converted for print. Checking a printed proof is the best way to see the true colour before a full run.
What colour mode should business cards and flyers be?
CMYK. Any piece that’s going to be physically printed should be set to CMYK before it’s sent, business cards and flyers included.
Does it cost more to print in CMYK?
No. Standard full-colour printing is CMYK as standard, so there’s no extra cost for setting your file up correctly. The only time colour affects price is if you specifically need Pantone spot colours for exact brand matching.
Related reading
For more on getting print-ready files right, see our printing page for the full range of what we produce, or upload your artwork and we’ll check it before we print.
Written by a member of the Express Copy team, Coulsdon. Express Copy has been printing for local businesses and individuals across Croydon and Coulsdon for over 50 years, handling everything from business cards and flyers to large-format banners and booklets.
