RGB, CMYK, and PMS – Trying to Capture Color in a Code
If you tell me you want a green table throw, a green backdrop, or even a green logo — how will I know which color you mean? Even if you give me a standard description, like “Kelly Green”, how can you be sure you will get the color you want?
How can we be sure we reproduce the color you’re expecting?
What we need is to define colors using a system that can be communicated and then used and re-used consistently.
The way this is done is with codes. As it turns out though, we need more than one way to describe color.
There’s one set of codes used for when dealing with images carried by light (TV or computer monitor), another for printing, and another entirely when we’re dealing with “spot” imprinting on t-shirts.
These codes are called RGB, CMYK, and PMS. Each of these is important for different marketing projects. We run into a fair amount of confusion on the meanings and uses of these codes, so I thought I’d give a basic tutorial here. I’m not a graphic artist, however, so my definitions and examples are definitely based in the products used in tradeshow displays and event products.
RGB (Red, Green, and Blue)
RGB stands for Red Green and Blue. If we mix – i.e. overlap – light of these three colors, we will get white light. You might remember seeing a demonstration of this on a trip to a science museum.
Colors which when you add them together get lighter are called “additive colors”. By defining how “bright” each of these colors is, on a scale from 0 to 255, you can “add” them together to get different colors. (255,0,0) is pure Red, (0,255,0) is Green.
RGB codes cannot be used to define and reproduce all colors, only those that can be created by “adding” these three colors together.
An enhanced version of RGB coding is used for computer monitors, television screens and other electronic devices which are “colored” by means of rays of light.
Have you ever experienced surprise when your printer prints a “different color” than what you see on your monitor? Or discovered your company website colors look different on your home computer monitor? It’s because one issue with RGB is the codes are not device-independent. The same code combination on one device will NOT look exactly the same on another device.
Also, if your graphic artist is most familiar with designing for computer websites, they may naturally try to provide you graphic codes for your logo using RGB. These codes are not useful for the printing processes used for the paper, vinyl, or fabric materials used in trade show and event products.
CMYK (Cyan, Magenta, Yellow, Black) – also known as Process Color or “4 color printing”
You can create a wide range of colors by using different combinations of the colors cyan, magenta and yellow. Adding these three colors mixed together in equal amounts creates a color near black; these are called the three subtractive primaries. Including true black as a fourth color gives you a more realistic result.
With CMYK printing, a series of dots are printed, in layers, of each of these colors with the net result creating a complete picture. This is often called “process color” or “four color” printing.
It’s actually possible to add more standard color dots to create a wider range of final color, so you will sometimes see “six color” or “eight color” printing. For instance, by breaking cyan into light cyan and dark cyans, and the same with magenta, you will have “six color” printing, which allows your printer to produce yet more realistic color.
Process color is used for printing photographs and graphic images. Because it can reproduce complex colored images, including shading, gradients, and drop shadows – it is often referred to as “full color” processing/
If you’ve ever seen a picture where one of the plates used for printing is off, even a little bit (perhaps — back in the day — on the funny pages of a newspaper) you know how much this process depends on exact alignment to create the effect using the mix of colors.
In the tradeshow and events world, digital printing or dye sublimation (which both use process color/CMYK) are typically used for your display graphics, whether they are printed on vinyl, solid substrate or fabric material.
Spot Color Printing Using the Pantone Matching System (aka PMS codes)
With spot color, a precisely pre-mixed color of ink is directly applied to the paper or fabric material. This allows the use of a relatively exact color which can be replicated time after time. PMS Codes are normally used when a small number of precisely defined colors are needed.
Spot colors are used to replicate logos consistently. They cannot be used for artwork with gradients, shading, or drop shadows.
The most common system used to define spot colors is the Pantone Matching System a.k.a. PMS codes. Pantone(R) provides a system for carefully calibrating colors across a wide range of printing processes and printing machinery.
Sometimes both Spot and Process are used together — for instance on company brochures or catalogs – when precise colors are needed for logos, and a wider range of colors are needed to represent the company’s products.
Examples in the tradeshow and events world include screenprinted items such as T-shirts and table throws, and padprinted promotional items.
As confusing as it is, you will sometimes be asked for your “PMS numbers” even when working in a medium that does not use them – i.e. CMYK digital printing. This is to provide a “sync up” point, to try to get certain especially important colors (i.e. for your logo) using the more universal system, in order to get as close a match as possible, within the limits of the other systems.
Conversion Between Color Codes
It is not possible to convert precisely between these different color code systems.
Sometimes a piece of art prepared according to one of these color-coded systems must be used on a project which requires a different code. It is rarely possible to make a direct match between these code systems.
This is why you will sometimes see “close PMS matching only” on a product description — for instance, when your logo is being printed digitally (using CMYK or 4 color processing).
Of course, our production artists are trained and work hard to make as close a match as possible so your marketing materials and tradeshow products will work together, but there are limits to what we can do.
Occasionally we find that a graphic artist you have hired — who typically works on one type of project which uses one kind of color code — is not familiar with the others. They may try insist that we should be able to use what they provide. Now you will know better!
You should now be better prepared to understand why a particular project we’re working on for you requires your artwork to be prepared in a particular manner. Less mystery for you and we can work with you more easily to get the results you are looking for!