RGB to CMYK Converter

Looking for a RGB to CMYK converter? Here’s a free tool to convert RGB to CMYK without losing color.

Enter RGB Values

Conversions

Code	Value	HTML/CSS
CMYK
Exact CMYK
Hex
RGB
RGB Percentage
HSL
HSV

Understanding RGB and CMYK Color Models

Before delving into the conversion process, let’s understand the fundamental differences between RGB and CMYK color models.

RGB

RGB is an additive color model primarily used for digital design. This color space is used for displays, including smartphones, computer screens, laptop displays and television.
It consists of three primary colors: Red, Green, and Blue.
Colors are created by adding various intensities of these three colors.
In the RGB color space, each color channel (R, G and B) is represented by a value ranging from 0 to 255. These values indicate the intensity of each color component, with 0 representing no color and 255 indicating full intensity.
RGB(0, 0, 0) represents a total absence of light, or black. On the other side, RGB(255,255,255) means white.

CMYK

CMYK is a subtractive color model designed for printing.
It comprises four ink colors: Cyan, Magenta, Yellow, and Key (Black).
Printers use these subtractive inks as well as reflected light to render colors on paper.
CMYK colors are represented in percentages, with 0% being white and 100% representing full ink saturation.
CMYK(0, 0, 0, 0) represents white. Thus, if you subtract no color, you get white.

How to Convert RGB to CMYK

Converting colors from RGB (Red, Green, Blue) to CMYK (Cyan, Magenta, Yellow, Key/Black) involves a more complex process because these color models operate differently. RGB is an additive color model used for digital displays, while CMYK is a subtractive color model used in printing.

RGB to CMYK Conversion Formula

Here’s a step-by-step explanation of the RGB to CMYK conversion formula:

Normalize the RGB values

Divide each of the RGB components (R, G, and B) by 255 to obtain values in the range of 0 to 1. This step is essential because RGB values are typically expressed on a scale of 0 to 255. By normalizing these values, you will get values between 0 and 1.

Calculate K from RGB

In order to calculate the Black Key (K) value, you have to determine the maximum of the R, G, and B values. Then, K is simply calculated as 1 minus the maximum value of the RGB:

K = 1 - max(R', G', B')

Calculate C from R and K

C is determined from the normalized Red and the Black Key (K).

C = (1 - R' - K) / (1 - K)

Calculate M from G and K

M is determined from the normalized Green and the Black Key (K).

M = (1 - G' - K) / (1 - K)

Calculate Y from Blue and K

Y is determined from the normalized Blue and the Black Key (K).

Y = (1 - B' - K) / (1 - K)

Conversion of RGB to CMYK Using the Formula

Suppose we have RGB values 255, 0, 0.

First, let’s normalize the RGB values:

R' = 255 / 255 = 1
G' = 0 / 255 = 0
B' = 0 / 255 = 0

Now, start by getting the Black Key (K) value:

K = 1 - max(R', G', B')
K = 1 - max(1, 0, 0)
K = 1 - 1 = 0

Then calculate the Cyan (C) value:

C = (1 - R' - K) / (1 - K)
C = (1 - 1 - 0) / (1 - 0)
C = 0 / 1 = 0

Then get the Magenta (M) value:

M = (1 - G' - K) / (1 - K)
M = (1 - 0 - 0) / (1 - 0)
M = 1 / 1 = 1

And finally, extract the Yellow (Y) value:

Y = (1 - B' - K) / (1 - K)
Y = (1 - 0 - 0) / (1 - 0)
Y = 1 / 1 = 1

So, the CMYK values for RGB(255, 0, 0) are:

Cyan (C) = 0%
Magenta (M) = 100%
Yellow (Y) = 100%
Black Key (K) = 0%

Why Convert RGB to CMYK

Converting RGB images to CMYK is essential for maintaining color accuracy when preparing printing materials. Here are some key reasons why this conversion is necessary:

Color Consistency

Printing in CMYK ensures that the colors on your final printed materials closely match what you see on your computer screen.
RGB colors can be significantly different from CMYK colors, leading to unexpected results when printing.

Achieving Desired Output

To produce images with specific colors, converting to CMYK is essential. Certain colors are only achievable in CMYK, especially neon colors.

Compatibility with Printing Technology

Many professional printers and printing processes require CMYK files for accurate color reproduction.
Using RGB images may lead to misinterpretation of colors by the printing equipment.