CMYK vs. RGB vs. Spot – What does it all mean?
By: Stephen Plumbley
This is a question we get a lot here at Spartan. What is the difference between CMYK and RGB, and why does it matter? It gets even more confusing when you bring Spot colors into the mix.
To start with, CMYK stands for Cyan, Magenta, Yellow, and Key. Key? What color is “Key”? Well, in a nutshell, it’s black. The other three ink color plates are keyed to the black plate, hence the name. RGB stands for Red, Green, and Blue. The key difference between CMYK and RGB is how they function. As you add the four CMYK ink colors together, you get progressively darker and darker colors until you end up with black. CMYK is based on pigments. RGB, by contrast, is based on light. If you add all three colors together, you get pure white. In effect, CMYK and RGB are foils to eachother. CYMK is also referred to as process, or 4-color process.
Lastly, when we are talking about spot colors, we are usually referring to Pantone Matching System, or PMS, ink colors. (There are other systems out there, but Pantone is the most recognizable.) PMS colors are based on a numbering system, and each ink has a specific color breakdown or value. It allows for very precise matching between products, paper stocks and printers. If an ink is specified as PMS 113 for instance, it is understood to be a very specific sunny yellow ink. Spot colors tend to be used where cost is a deciding factor, full color/CMYK printing is not necessary, or in conjunction with CMYK to achieve a specific color, such as on a logo.
So why does it matter?
Well, in the printing world it matters because you need to make sure your files are set up correctly for optimal reproduction. When we receive an RGB file, it has to be converted to CMYK in order to be printed. When that happens, color shifting can and will occur. Sometimes it’s hardly noticeable, sometimes the effect can be dramatic. The image below shows the difference between the two.
The same goes for PMS colors. If your piece needs a spot color, by all means, specify your specific PMS color. However, if it is ultimately going to print as CMYK only, be sure to convert your PMS color swatches to CMYK before providing us your finished files. That way you get exactly what you’re expecting on your end product.