By Jason Wilson
January 04, 2021
Color is an amazing thing. Everything has color. We find color at home, in the woods, in the sky, in the sea, in our clothes and in our food. Color changes how we look at things. It effects our opinion and even our mood. Throughout human history color has been given attributes, emotions and character. People easily identify with color.
We even have favorites.
Oddly enough however, most people do not understand color.
To really understand color, we must first understand light.
Color, in its most basic sense, is nothing more or less than reflected light. Every material, whatever it may be, reflects a certain amount of the available light from its surface.
Light, whatever its source, may be, bounces off every object within our available vision and back to our eyes at (yes that’s right) the speed of light. That light then passes through the cones and rods in our eyes where it is interpreted for our brain. The color and quality of that light therefore has a direct effect on what we then perceive. When we refract that light, either through a prism or just see it through the moisture in the air from the rain, we are able to see a rainbow. When we do that we are seeing the component colors of light.
Color is 2 parts engineering and 1 part biology.
So what does that have to do with using color in printing?
Pretty much everything.
In order to recreate color accurately in both digital and print settings different color models have been developed. The two most important models are known as RGB and CMYK
Any photograph taken by a modern digital camera is taken in RGB color mode. RGB stands for Red, Green and, Blue. This color mode is used by your computer screen, your TV, your digital camera, your smart phone, and every other image capture device every created. That’s because RGB uses light to recreate the color we see. Just like our eyes. Each of those three colors are separated into what are called channels. Each channel has 255 levels. 255 levels of all three channels is pure white light and 0 of all three is pure black.
Now this color model produces an impressive range of color that, though not as complete as our own eyes, is so broad most people can’t really tell the difference.
Printing however is a different animal entirely. Whereas in RGB we are adding light to make things brighter, in printing we are adding ink to the physical surface of a material. This changes everything.
The CMYK color model is based on the simple principle that we teach to little children; all color can be made from the primary colors: Red, Yellow and Blue.
Well, that’s almost true.
Turns out, with varying levels of color purity in ink, materials and etc., red, yellow and blue don’t quite make every color. For starters they are too dark and all three combined comes up with a really dark brown instead of black. So Red has been replaced with Magenta and Blue with Cyan. These lighter colors allow for a wider color range.
K stands for black. Why? Great question with several possible answers. The most common being K stands for “Key” since black adds contrast and depth that the other colors just cannot create on their own, and K was originally used instead of B to prevent confusion with Blue since the original 4 color model did use Red Yellow and Blue (RYBK). The truth is, nobody ever seems to have written down why they did that so we may never know.
So K stands for black.
With the CMYK color model we are able to produce millions of colors. CMYK is a percentage based model from 0% to 100% in 4 separate channels. The color “gamut” or color range of CMYK is not as large as RGB but it is, once again, one of those things that comes with a “close enough” label. Most people can’t tell the difference.
As we add color in CMYK, the colors get darker, running the opposite direction of the RGB color model. This creates a need in the designer to understand both models and how any editing they do to them will affect the outcome.
Now comes the tricky part.
Most people don’t have high end image editing software. Most people don’t understand or have even heard of RGB and CMYK color models. Most people just take a picture and want to print it out on their deskjet printer. Because of this group of reasons, the desktop printer industry did something both extremely convenient and at times very frustrating.
They made all the default setting on home printers RGB.
Now that is great for the folks at home who don’t know, don’t care, and just want a pretty picture today.
For those of us in the printing industry however, it can be a real hassle.
You see, now a print off your home printer will not look the same as the one from the print shop. The deskjet uses an ink that is sprayed onto the page. The print shop is most likely running it on a high capacity copier that uses toner (Totally different material and another topic of its own) and are using different color settings.
But wait! There’s more.
Some of the new high end ink jet printers now also default to RGB, like the wide format Epson printer that sits next to my desk at work. She is a thing of beauty and does fantastic work. But she prints her best colors with RGB.
My plate setter that sits to the other side of me however, she does not like RGB.
No indeed, she does not.
You always know when an RGB image has snuck through to the test print on the plate setter. Those come out dark and drab looking, instead of colorful and vibrant. This is why we have several options to preflight a job and check it over before sending it over to make plates and run the job.
This is why a print shop will almost always ask you, “Are your graphics RGB or CMYK?”
If you don’t know, just go ahead and say so. We totally understand.
And we have a solutions for that.