Why Colors Look Different In Print

Am I Blue?

“Colour isn't something we see; it's something we think. “ 

— Paul Simpson, (The Colour Code; London: Profile Books 2021)

Light is made up of wavelengths.  Some of those can be seen by humans, so we call them the visible spectrum. Other wavelengths are in light, too, like ultraviolet, invisible to us, but pretty useful to moths. When we were young, or at least those of us who pre-date computers in education, the primary colors were taught to us: Red, Yellow and Blue. This was a model that was dominant from the seventeenth century and has formed the basis of color theory education in the west for many years. These three colors, when mixed in paint, will give you all other possible colors. Yellow and Blue, for instance, make Green. They are the building blocks, and cannot be produced by other colors combined. Or so the orthodoxy says.

But physicists, churlish and unruly as they are, would have none of it. Red, Green and Blue are the primary colors.  Mix Green with Red and you get Yellow! To make matters worse, Green and Blue give a terrible blue called Cyan, and Red and Blue also give a terrible color, Magenta. Mix the primaries, in equal measure, and you get white. 

So, thanks to those pesky physics nerds, we get two things that are interlocked the Red-Green-Blue (RGB) model and the Cyan-Yellow-Magenta (CYM) model. Your LCD monitor on your iPad, your iPhone, your iMonitor, your iWatch and all the other iDevices in your world have Red, Green and Blue lights, itty-bitty lights, that trick you into seeing billions of colors as they beam at your retina. The relative proportions of those three beams determines the color you perceive. Proportion becomes important later. 

In a similar manner, CYM has come to be the standard for reflected light, like off of a piece of paper. Billions of itty-bitty partly translucent ink or toner dots snuggle up to each other (with some overlap) to create the rainbow of colors in printed material. It’s known as 4-color process. Four?  Yes, just like R+G+B creates white, C+Y+M produces black, which they called ‘K’ so it would feel cool. It’s added in to the mix as a pure color of ink or toner because our eyes are very good at detecting when something goofy is going on with black.  Unless the mix is absolutely perfect on a perfect surface, the black from CMY isn’t super great, and additionally, it’s the most common color things are printed in, so it is far more economical to have K added to the group. The useful third wheel of printer inks. 

The models, CYMK for printing and RGB for monitors are different, though related. The way the colors are made has to essentially be translated from one to the other. Simple, right? No, of course not. At first the actual RGB wavelengths used were constrained by the ability to create them with existing technology.  Then people started to grouse and moan and insist a better TV experience, so the wavelengths shifted to meet demand.  It’s not all science and engineering, it’s also taste and preference that make an RGB monitor.

Just to really lean into this, the CYMK model is all well and good, but rather than the 3 or usually 4 colors applied to make a tone, many modern printers are hexachromic (there’s a crossword answer if ever I saw one) using six colors, others are octochromic.

So, if they’re just two models, just translate!

Oh, were life so simple!  We discussed hue, the actual color, above. What we have ignored is the intensity of the hue, known as saturation. Nor have we discussed the lightness or darkness, the value, of the hue.  Both of these, saturation and value, are achieved in the two mediums in different ways and other factors come into play. Monitors can be mis-calibrated, or purpose built with filters like for video gaming. Printing happens on papers that have different levels of reflectivity, and even pure white paper is always a little cool or a little warm, which can have a profound effect on the perception of color. Monitors can produce many more colors than printers can. 

A color picker with our friend Yellow dialed in. Note the values in the left column vs those in the right. 

Okay, So No Perfect Solution?

There really isn’t a perfect solution, but there are some near perfect ones. The first part of the solution is to set realistic expectations.  A conscientious print house, like Betts, will do everything they can to make sure their machines are calibrated to standards, but variations are to be expected and really, unavoidable. If we tweak the rose color, it will change other colors, too. If the pink is bright on your screen, but not as bright in the print, we can bump the brightness, but we’ll also have to bump the contrast and that might make other colors too aggressive.  If your print is very nearly as desired, that is a reasonable expectation. Even when scanning a print, the chemical nature of the media can’t be matched in the reproduction, for example, fluorescent inks don’t exist in an archival inkjet, so there is no way to reproduce the fluorescence exactly. 

On your part, design or work in CMYK formats in your software of choice.  When working with colors, use Pantone numbers for the CYMK values to reach an agreed upon understanding of what the color should be.