RGB to CMYK Converter
Free, accurate, and instant conversion. Preview your color in real-time on digital and print mockups.
Source Input RGB
/* CSS Variable */ --color-primary: #000000; /* Standard */ color: #000000; background-color: #000000;
From Screen to Press: RGB to CMYK
We live in a digital world designed in RGB (Red, Green, Blue). Cameras capture it, monitors display it, and scanners read it. However, the physical world of packaging, magazines, and business cards still relies on CMYK ink.
This converter is the critical checkpoint. It translates the light-based colors of your screen into the pigment-based recipes (Cyan, Magenta, Yellow, Key) for the printing press, alerting you to any colors that might lose their vibrancy in the transition.
RGB (Input)
Additive Model. Used for screens. Capable of displaying millions of bright, saturated colors.
The Limit
The "Gamut Warning." Ink cannot physically be as bright as a light pixel. Some clipping occurs.
CMYK (Output)
Subtractive Model. Used for print. Four ink plates combine to create the final image.
Understanding the "GCR" (Black Generation)
Converting to CMYK isn't as simple as 1+1=2. You can make dark grey using equal parts Cyan, Magenta, and Yellow (CMY), OR using just Black ink (K).
Why We Add 'K' (Key/Black)
- • Theoretically C+M+Y = Black. Practically, it makes a muddy brown "registration black" that soaks the paper.
- • GCR (Gray Component Replacement) replaces the grey parts of C/M/Y mix with pure Black ink.
- • This saves money on colored ink, allows paper to dry faster, and creates sharper text.
- • Use Rich Black (60,40,40,100) for large areas, Plain Black (0,0,0,100) for text.
Common RGB to CMYK Shifts
| Color | RGB (Screen) | CMYK (Print) | Result |
|---|---|---|---|
| Electric Blue | 0, 0, 255 | 100, 100, 0, 0 | Becomes purple/violet. |
| Lime Green | 0, 255, 0 | 100, 0, 100, 0 | Dulls significantly to a forest green. |
| White | 255, 255, 255 | 0, 0, 0, 0 | Use the paper color (no ink). |
| Black | 0, 0, 0 | 0, 0, 0, 100 | Standard Black. |
Who is This Tool For?
Graphic Designers
Prepare digital designs for professional printing—brochures, posters, business cards, and packaging.
Print Shop Operators
Verify client files are print-ready and identify colors that may shift during production.
Marketing Teams
Ensure brand colors are consistent from digital campaigns to printed materials.
Photographers
Convert edited photos for print publications, galleries, or physical photo products.
Frequently Asked Questions
Why are RGB and CMYK different?
RGB is additive (Light): Red + Green + Blue = White. CMYK is subtractive (Pigment): Cyan + Magenta + Yellow = Black (Mud). They are physical opposites.
Why did my bright green become dull?
The RGB color gamut is much larger than CMYK. Bright/Neon colors (like RGB 0, 255, 0) result from pure emitted light. Paper cannot emit light. To print that color, you would need special fluorescent spot ink.
What is 'Gamut Warning'?
It alerts you that the color you selected on screen physically cannot be reproduced with standard 4-color process inks. The converter will choose the closest possible duller match.
Should I work in RGB or CMYK?
Design in RGB for flexibility and file size. Convert to CMYK only at the very end when creating the final Print PDF.
What is 'Rich Black' vs 'Plain Black'?
Plain Black is just K (0,0,0,100). It is perfect for text. Rich Black mixes in other colors (e.g., 60,40,40,100) to create a darker, deeper tone for large shapes.
Why is my file size bigger in CMYK?
RGB has 3 channels. CMYK has 4 channels. This means every pixel needs 33% more data to describe itself, resulting in larger file sizes.
Can I convert CMYK back to RGB without loss?
Yes, usually. Converting CMYK → RGB is safe because the RGB gamut is larger. However, converting RGB → CMYK → RGB is destructive because you lose the bright colors in the middle step.
Does this tool use ICC Profiles?
We use a standard generic conversion valid for most digital presses. For high-end offset printing, consult your print shop for their specific ICC profile (like GRACOL or FOGRA).
Why is pure RGB blue (0,0,255) purple in print?
Pure blue light is very energetic. To mimic it with ink, printers mix Cyan and Magenta. Often, this mix leans too heavily on Magenta, appearing slightly purple/violet on paper.
What is 300 DPI?
Dots Per Inch. While CMYK is the color mode, 300 DPI is the resolution standard for crisp printing. Web images differ; they are usually 72 DPI.
What is total ink coverage and why does it matter?
Total ink coverage is the sum of C+M+Y+K percentages. Most printers have a maximum limit (usually 280-320%). Exceeding this can cause smearing, slow drying, or paper damage. Rich Black (60,40,40,100 = 240%) stays within safe limits.
How do I prepare a file for professional printing?
Convert to CMYK mode, set resolution to 300 DPI, add bleed (usually 3mm) around edges, embed fonts or convert to outlines, and export as PDF/X-1a or PDF/X-4 format. Always request a proof print before the full run.