When it comes to design, there are many different color models available, most applications use either RGB or CMYK. It's highly important for a graphic designer to know the difference, and know when to use or not to use a color model. But if you're considering shelling out the money on design work, you should know the difference, too!
Why?
As a graphic designer and small run printer, I can't count the number of times a client or customer has asked me to print a file that was designed within the wrong color model or resolution. After explaining to the client what I can do to fix the problem, but also explaining why there is a problem - most are 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 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 models (to the left) 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 model.
If you'd like to learn more about RGB color models, try giving this Wikipedia article a read.
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.
So 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 reduces ink usage of the other tones.
CMYK is also a device dependent color model, but it is most frequently used to this day as the main color model used in printing. If you'd like to learn more, check out Wikipedia.
So what's the big deal?
Since both color models are device dependent, they will display differently depending on the medium in which they are presented.
For instance, an RGB color model is ideal for an electronic source - such as your computer's monitor, but due to the additive nature of the color model, 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 model 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, CMYK color models are not appropriate.
Did I lose you yet?
The best way to illustrate the difference is with some show and tell. Above to the left is color swatches of Red, Green, and Blue followed by Cyan, Magenta, and Yellow. On the left side of the swatches, the color model 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! 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, if you enlarge the swatch, 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 model 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 model.
Anything that could ever be used for print should be designed with a CMYK color model.
If you aren't sure of the application, request files in BOTH color models, just in case. Better safe, than sorry, right?
