Color Spaces: Explained

Learn about the two different color spaces most used in art and how/when to use them.

Knowing the differences between the color profiles can help you to understand how different printing processes work and how those processes will affect your printed images.

RGB

Red. Green. Blue.

Color Type: Additive Color
Used for: Screens

Every color we see on a device has a combination of R, G, and B to trick our eyes into seeing just one color. RGB Colors combine to produce WHITE with additive color processing.

For example, if you wanted to show something yellow, the pixel on your screen shines red and green light together, while leaving the blue one off. Meaning, your values for Red and Green would be at a full 255.

The stronger the light intensity, the brighter the colors appear. When all 3 colors are combined at full intensity (255), they display as white on your screen. At no intensity (value 0), they appear as black on your screen.

Even though RGB is present on all electronic devices, the colors may vary across systems and models as well as brightness, contrast, and gamma settings.

CMYK

Red. Green. Blue.

Color Type: Subtractive Color
Used for: Printing

This four-color process works for any type of printer and colors seen are limited to what CYMK ink can combine to make.

CMYK Colors combine to produce a BLACK-ish hue with subtractive color processing.

With CMYK, color intensity is not as flexible as in RGB. It’s just impossible to replicate on ink paper or fabric the same intensity and brightness that a digital display can.

This means some RGB colors will show up differently when printed in CMYK. And some colors cannot be printed at all due to the limitation of how C, M, Y, and K mix.

With CMYK, color intensity is not as flexible as in RGB.
It’s just impossible to replicate on ink paper or fabric the same intensity and brightness that a digital display can show.

This means some RGB colors will show up differently when printed in CMYK.

Although all printers print in CMYK, the end result may vary depending on models and substrate. (Like using see-through or different colored materials).

What's the Difference between RGB & CMYK?

The visible spectrum of light that the average human eye can see is comprised of billions of colors.

RGB on screens is capable of showing about 16.7 million.

However, printers can only reproduce a limited color spectrum.

Color Gamut

In Photoshop, specifically, there is a way to know if the color you're using is safe to print.
With a CMYK file open, if you go to View > Gamut Warning (Ctrl+Shift+Y), it will "gray out" the colors in your file to show what colors are not print-safe (out of the color gamut).

If you open the Color Picker and use the same shortcut (Ctrl+Shift+Y), it will "gray out" colors out of the color gamut within the Color Picker to help you choose colors.

How to Convert RGB to CMYK?

In Photoshop, you can change the color mode of the document by going to Edit > Mode > CMYK Color
However, I recommend a different method.

Go to Edit > Convert to Profile
Select CMYK, and use Working CMYK - US Web Coated