Designing for print? Use our free RGB to CMYK colour converter to see exactly how your screen colours will translate to print.
Unlike basic converters, this tool uses CIE Delta-E 2000 colour science to measure the precise difference between your on-screen colour and the printed result, with simulations for coated, uncoated and newsprint paper stocks. Upload an image to preview your entire design in CMYK, or build a palette and check every colour before you send artwork to press.
Imperceptible — colour will print accurately
Drop an image here or click to upload
JPG, PNG, WebP — processed entirely in your browserAdd colours to see how your entire palette converts to CMYK. Click any swatch to edit.
Common Problem Colours in CMYK
These RGB colours are known to shift significantly when converted to CMYK for printing. Hover over each to see the expected print result.
Why RGB and CMYK Produce Different Colours
Every colour you see on your monitor is created by mixing red, green and blue light. This is called the RGB colour model, and it works by adding light together — the more you add, the closer you get to white. Printers work in the opposite direction. They use cyan, magenta, yellow and black inks (CMYK) to absorb light from white paper. The more ink you apply, the closer you get to black. This fundamental difference means that some colours you can display on screen simply cannot be reproduced with ink on paper.
The range of colours a system can produce is called its gamut. The sRGB gamut used by most monitors is significantly larger than the CMYK gamut used in offset and digital printing. Vivid greens, electric blues, neon pinks and bright purples are the most common casualties — they sit outside the CMYK boundary and will appear duller or shifted when printed. Our converter highlights these problem colours automatically and suggests the closest printable alternative.
Understanding Delta-E: How We Measure Colour Accuracy
Delta-E (written ΔE) is the standard metric for measuring the perceived difference between two colours. Our tool uses the CIE DE2000 formula, which is the most advanced and perceptually accurate version of the Delta-E standard. It accounts for the way human vision is more sensitive to certain colour shifts than others — for example, we notice changes in skin tones and neutral greys far more than shifts in saturated reds.
| ΔE Value | What It Means |
|---|---|
| Less than 1 | Imperceptible — no visible difference between screen and print |
| 1 to 2 | Barely noticeable — only visible side by side under controlled lighting |
| 2 to 5 | Noticeable — a slight shift that is usually acceptable for commercial print |
| 5 to 10 | Significant — the printed colour will look noticeably different |
| Above 10 | Very different — consider choosing an alternative colour or using spot inks |
Most commercial printing considers a ΔE below 3 to be acceptable. For brand-critical colours where accuracy matters — logos, Pantone swatches, skin tones — aim for a ΔE below
How Paper Stock Affects Your Colours
The same CMYK values will produce different results depending on the paper you print on. Our tool lets you switch between three common print profiles to see the difference:
Coated paper (glossy or silk) has a smooth, sealed surface that holds ink on top of the sheet. Dot gain is minimal, colours appear vibrant, and the gamut is at its widest. This is the standard stock for sticker and label printing, product packaging, brochures and marketing materials.
Uncoated paper (matte or bond) absorbs ink into its fibres, causing dots to spread — a phenomenon called dot gain. Colours appear softer and slightly warmer due to the yellowish paper tone. This stock suits letterheads, books and eco-friendly packaging where a natural, tactile finish is preferred.
Newsprint has the highest dot gain and the narrowest gamut. Ink spreads significantly into the porous fibres, shadows fill in, and highlights appear muddy. Designs intended for newspaper reproduction should use bold, high-contrast artwork and avoid subtle gradients.
How to Use the Image Preview
Upload any JPG, PNG or WebP file and the tool will convert every pixel from RGB to CMYK using a print-profile simulation with dot gain modelling. Drag the comparison slider to reveal the difference between your original design and how it will appear in print.
The statistics panel shows three key metrics:
- Pixels analysed — the total number of pixels processed
- Out of gamut — the percentage of pixels with a ΔE above 3, meaning they will shift noticeably in print
- Average ΔE — the mean colour difference across the entire image
Click Highlight Out-of-Gamut Areas to overlay a red tint on every pixel that falls outside the CMYK gamut. This is especially useful for catching small areas of problem colour that you might miss — a gradient that dips into neon territory, a shadow with an electric blue cast, or a logo colour that sits right on the gamut boundary.
Colours That Cause Problems in CMYK Printing
If you are designing for print, these are the colours to watch:
Neon and fluorescent greens are the single hardest colour family to reproduce in CMYK. Pure RGB green (0, 255, 0) has a ΔE above 30 when converted — the printed version will look like a completely different colour. If your brand uses a vivid green, consider specifying it as a Pantone spot colour for accurate reproduction.
Electric and royal blues lose significant saturation. The deep, vivid blue you see on screen will print as a more muted, slightly purplish tone. Reducing the brightness of your blue slightly during the design stage can help minimise the surprise.
Bright purples and violets shift towards blue or appear muddy in CMYK. Increasing the magenta component in your design can help maintain the sense of vibrancy, though a true violet is difficult to achieve with process inks alone.
Hot pinks and neon magentas fall outside the gamut and will print duller than expected. For packaging and stickers where a fluorescent pink is essential, fluorescent inks or Pantone neon swatches are the only way to achieve an accurate match.
Vivid oranges are generally reproducible in CMYK but can shift slightly towards red or yellow depending on the ink balance. Ensure both your magenta and yellow values are high for the best result.
Tips for Designing Print-Ready Artwork
- Design in CMYK from the start. Most design applications let you set the document colour mode before you begin. In Photoshop, choose Edit → Convert to Profile → ISO Coated v2. In Illustrator, choose File → Document Color Mode → CMYK. This ensures the colours you pick are achievable in print.
- Check your brand colours early. Run your logo colours through the converter above before committing to a design. If your brand palette includes out-of-gamut colours, decide upfront whether to adjust them for CMYK or specify Pantone spot inks.
- Use the image preview for final artwork. Before sending files to your printer, upload your finished design and check the comparison. Pay close attention to gradients, photographic images and areas with high saturation.
- Choose the right profile for your stock. If you are printing stickers on glossy vinyl, use the coated profile. If you are printing on kraft or recycled paper, the uncoated profile will give you a more realistic preview.
- Avoid using pure black (0, 0, 0) for large areas. In CMYK, this produces a thin, washed-out black. Instead, use a rich black — typically C60 M40 Y40 K100 — for solid backgrounds and large text. Avoid rich black for body text, as the multiple ink layers can cause registration issues at small sizes.
Frequently ASKED Questions
Common questions about RGB to CMYK colour conversion, print colour accuracy and preparing artwork for professional printing.