How to Convert RGB to CMYK Numbers

Manual color conversion from online to print formats is complex.

One of the ironies in preparing a digital image for print is the way the colors are displayed. Computer monitors use a combination of red, green and blue (RGB) light to produce the spectrum of colors you see in the image. When printing the image onto paper, a different set of colors is used. Cyan, magenta, yellow and black combine to create the printed image. Though CMYK support is difficult to find in many photo-editing and paint programs, you can convert the RGB values into comparable CMYK values using an online conversion tool.

Instructions

1. Select and open a website that converts RGB color values to CMYK color values, such as Forret, JavaScripter.net or EasyRGB. Most of these online tools are Internet browser applications that perform the calculations for you after you enter in RGB values. Some sites provide multiple types of conversion. Ensure that you select a site that converts RGB to CMYK.

2. Enter the numbers into the R, G and B fields in the converter form. The numbers for each value can range from 0 to 255.

3. Click the button that converts the values.

4. Record the new values for C, M, Y and K. The numbers for each value will range from 0 to 1.

Tips & Warnings

• Conversion formulas used by online tools are based on complex algorithms that make certain assumptions. The values converted from RGB to CMYK are an approximation and might not exactly match the RGB color, especially when printed.

References

• Designer-Info.com; RGB to CMYK — Gamut Warning; Tom Arah; March 2003

Resources

• Forret; Color Conversion (RGB / CMYK / HSV / YUV / ...)
• JavaScripter.net; RGB-to-CMYK Color Conversion
• EasyRGB; Color Calculator