Here at Esigns we print a lot of vinyl banners and we get and get asked a lot of questions here about color. The most common one is "Should I set my file to CMYK or RGB colors?" Many others ask "Why does that matter?" and "What are you talking about?" Well, I'd like to answer those questions.
Before we go into that, lets talk about how colors are produced naturally. Colors are produced by the light that is reflected off of an object. Objects that are a certain color will absorb all other light except for that one. I see the colors I see because its what they bounce off of themselves and into my eyeballs. I can't see a can of coke as green because it absorbs that particular color, so it doesn't reflect off the can into my eyes. It can be kind of confusing but it's an important concept to keep in mind when discussing colors.
RGB vs CMYK
The two most widely used color modes are CMYK and RGB. CMYK is usually designated for print media (vinyl banners, books, flyers etc.) while RGB is used for digital media (websites, television, digital graphics). The color mode is determined by how the color is produced or how the colors get from white to black and back again.
What does RGB and CMYK stand for?
RGB and CMYK represent the colors that are used in each color profile. RGB stands for Red, Green and Blue. CMYK stands for Cyan, Magenta, Yellow and Black. Why use K for black? When color printers were being designed they originally used Cyan, Magenta, and Yellow but those alone were not producing satisfactory results. The makers of the printers discovered that black was the "key" to producing the colors they wanted and thus the "K" for black.
CMYK colors are known as subtractive colors. When you print, you usually start with white paper or some other media. Yes, there are colored papers out there but for the sake of clarity, we will pretend they don't exist. To produce the colors, you add ink to the media which then makes it darker. You are subtracting the light that is reflected off of the material and it produces the color. When all of the colors are added to their fullest degree you get black. CMYK is percentage based and the K is just extra, leaving us with about 1,000,000 million colors that we can print.
RGB colors are known as additive colors and essentially works in the exact opposite way of CMYK. When your computer or TV screen is not displaying anything, it is black and is not producing any light. To get color on your screen the pixels add light in varying degrees to produce a wide gamut of color. When all of the colors are added to their fullest degree you get white. RGB, being light based, uses 256 levels of brightness for their three colors, meaning 16,777,216 color possibilities. That number again, so you know it wasn't a typo, is sixteen million, seven hundred seventy-seven thousand, two hundred sixteen.
What should I use?
When we print your banners and signs we actually set the files to RGB. Even though our printers use CMYK keep them calibrated to "fake" RGB colors and make sure that the colors that are seen on the screen are the colors that you receive. So, long answer short, either works fine but know its CMYK printing as closely as possible as RGB.
If you would like to learn about the difference between Pantone and CMYK check us out on facebook.