You’ve probably heard people talking about RGB and CMYK, and you probably figured it was information you’d never really need. On the other hand, you may have been asked to convert something from RGB to CMYK or vice versa, whether at work or for a friend.
So what’s the difference, and why do you need to know?
Essentially, the difference between RGB and CMYK is a difference between the world of screens and the world of print. The vast majority of digital devices we use on a daily basis—computers, smartphones, tablets, cameras, scanners, TV screens—use combinations of Red, Green and Blue to display color. When we move into the real of paper and printing, the vast majority of commercial printers use a combination of Cyan, Magenta, Yellow and Key (black).
Are there exceptions? Is it possible to print RGB or display CMYK on a digital screen? Yes—but the results aren’t as good. That’s why RGB has become standard for the digital world, while CMYK is used to achieve the best results in print.
Both RGB and CMYK are essentially a way of “tricking” the eye into seeing the intended colors. On a digital screen, we’re seeing tiny pixels that have been projected to achieve the desired effect. On a piece of paper, we’re seeing dots of ink that actually subtract color. Paper and screens reflect light in different ways, so different color schema are necessary to create the colors we want.
Why does this matter?
The physics of light and color are all very interesting, but unless you’re interested in mastering commercial printing (or writing a dissertation on the properties of light), you probably don’t have much use for detailed technical explanations. All you need to know is that RGB is for digital materials (such as a header image for your Facebook page), while CMYK is for printed materials (such as your wedding invitation or direct mail brochure).
It’s also important to recognize that there is no exact translation between RGB and CMYK. Let’s say you design a brochure or advertisement on your computer, and after many long hours, you’ve got the design exactly how you want it. The colors are perfect. So you send the file to your print specialist and receive a surprise response: Your file was designed with RGB color. The printed version won’t look exactly the same.
Even worse, your printer might convert your RGB file to CMYK without saying anything. You’ll only discover the difference when you hold the printed version in your hands and notice how different it looks.
Here’s the solution…
If you’re designing something for print (using Photoshop, for example), always make sure to switch the color to CMYK before you begin. That way, you’ll see more or less exactly how the image will look on paper.
If you do design something in RGB and are forced to convert it to RGB, the difference may not bother you much. Some people are more sensitive to exact color matches than others. As long as you have a reputable print specialist on your side, you’ll be able to work out color issues before your project goes to print.