DIY Design: What's the difference between RGB and CMYK?

If you choose to DIY your design or hire a graphic designer, you might be a little confused about print and web specifications.

When it comes to design, there are many different color modes available, most applications use either RGB or CMYK. It's highly important for a graphic designer (whether that's you or someone you hire!) to know the difference, and know when to use or not to use a color mode.

In my previous life as a graphic designer and small run printer for Etsy biz owners, I can't count the number of times a client or customer asked me to print a file that was designed within the wrong color mode or resolution. After explaining to the client what I can do to fix the problem, but also explaining why there is a problem - most were upset that they didn't receive the "right" file from their original designer in the first place or never knew there was a difference!

So, let's iron this out so you know the difference between RGB and CMYK color modes, and when each should be used.

What's RGB?

RGB stands for Red, Green, Blue and is an additive color model. What this means is that this color model is based on adding and mixing light - when you add Red, Green, and Blue light together, you create a pure white.

You can see how adding pigments in RGB color modes affects the ultimate color result. As Red, Green, and Blue all come to white - it is understood that white is truly the combination of all colors and black is the absence of color.

RGB is primarily used for designing elements that will be displayed on a television set, a computer monitor, a mobile phone, or any other kind of light source. Obviously, it is a device dependent color mode.

And CMYK is?

CMYK stands for Cyan, Magenta, Yellow, Key (Black) and is a subtractive color model. A subtractive color model works exactly opposite from an additive color model (RGB,) it works by partially or entirely masking certain colors from white.

So instead of adding light to achieve a color, CMYK is using ink to subtract brightness from white. Therefore, Cyan, Magenta, and Yellow combined is black - the absence of brightness.

Where does the Key (Black) come in? In traditional printing, Cyan, Magenta, and Yellow inks were layered to create images. Eventually, Key (Black) began being used to additionally subtract brightness in printing (producing deeper darker tones) and heavily reduced ink usage of the other tones.

CMYK is also a device dependent color mode, but it is most frequently used to this day as the main color mode used in printing, whether it's posters, brochures, business cards, books, or magazines.

What's the big deal?

Since both color modes are device dependent, they will display differently depending on the medium in which they are presented.

For instance, an RGB color mode is ideal for an electronic source - such as your computer's monitor, but due to the additive nature of the color mode, printing is not ideal. With an additive color model, you are adding colors via light wavelengths and creating new colors by lightening the Red, Green, and Blue color model using more or less light - hence why an electronic source is best, you are using an abundance of light to communicate color.

While the CMYK color mode is ideal for printing, since the subtractive nature of the color model is subtracting the brightness from white (paper) by adding pigment. Since your computer monitor is emitting light and therefore attempting to communicate color with the addition of light, a CMYK color mode is not appropriate.

Did I lose you yet?

The best way to illustrate the difference is with some show and tell.

Check out the color swatches of Red, Green, and Blue followed by Cyan, Magenta, and Yellow. On the left side of the swatches, the color mode represented is RGB while the swatches on the right have been converted to CMYK.

Notice how the RGB colors are brighter, they're being communicated by a light source - your monitor on your computer or your screen on your phone or tablet. If you print those colors in CMYK, they will look like the right side - subtracting brightness from white.

The bottom swatch is a completely random brown tone, can you tell the difference?

I know that it's a lot to wrap your head around, but I find that showing exactly how a color can differ between RGB and CMYK usually makes the point clear - the RIGHT color mode needs to be used. If you are considering having a designer create for you, or maybe you're going to be brave and DIY - know what you need!

Anything that will be displayed on a light source or electronic device should be designed from start to finish with a RGB color mode.

Anything that could ever be used for print should be designed with a CMYK color mode.

If you aren't sure of the application, request or create files in BOTH color modes, just in case. Better safe, than sorry, right?