One of the most common complaints we hear from clients is that their print job doesn’t look as the same as it did on their computer screen. Color consistency is one of the biggest challenges in digital printing, mainly due to the way we talk about color in digital (on screen) and print media.
If you’ve ever done any design work, you’ve probably come across the terms RGB and CMYK. Both refer to a way to identify a color, but apart from that, they’re completely different. By incorrectly converting from one color type to another, you risk the chance of completely changing the hue in the final print. And submitting a print file to your printer that uses the wrong color mode can greatly effect the final results of your printed piece.
So what is the difference between all the various color modes? What is RGB? What is CMYK? Professionals group modes into either on-screen or print types. On-screen types use an additive process to produce a particular hue, while print types use a subtractive process to create the end pigment. These methods to process colors are one of the main reasons you can’t use an on-screen color type to give instructions to a printer and vice versa.
On-Screen Color Types
RGB is the most commonly used color type, and the one most people will have some experience within their day to day lives. The acronym stands for Red, Green, Blue, which are the starting points in making a wide range of colors. These three primary channels can combine to produce many other shades.
The process of creating a hue in RGB involves the addition (additive color) of the three primary colors. If you mix red and blue, you’ll get purple. Mix in a little bit more red and you’ll have a reddish-purple tint, and so on. Every color produced by RGB will have a particular intensity in each of the three main channels, allowing for hundreds of thousands of possibilities.
RGB can produce a fantastic array of bright, vivid colors that printing methods may struggle to reproduce. That’s why RGB is limited to digital devices, including television, computer screens, and digital photography.
Typically used in website development, Hex works in the same way as RGB and represents a different way of producing a color code. Instead of manually recording the intensity values of the red, green, and blue channels, a Hex color code is a combination of six letters and numbers representing the same values.
While you can do the conversion from RGB to Hex manually, the more natural way is to use any graphical program. Most graphic design programs like Photoshop or Illustrator have a converter already built-in.
Hex is typically used in website design and development and is basically a shorthand for expressing RGB color values. Having a short six-character code instead of a long string of numbers can simplify the process of identifying a particular hue.
Print Color Types
CMYK is an acronym for Cyan, Magenta, Yellow, and Black, which is the most common color type in the printing industry. Printing presses use these four base colors in some combination to produce millions of color shades and hues. Unlike on-screen modes, which add colors together, the printing process uses a subtractive model instead. Remember that white is the combination of all colors versus black with is the absence of all colors. Since in the printing process you are starting with (in most cases) a white piece of paper the CMYK model works by partially or entirely masking colors that would otherwise be reflected off the white paper.
In this model, colors absorb specific wavelengths of light that come off of a white background. The remaining wavelengths produce the image and pigments that you see.
A good way of understanding this model is to view every color as a filter. Cyan filters out red, magenta filters out green, and yellow filters out blue. Black filters out white and controls the vibrancy and saturation of the color palette.
CMYK is extremely popular in digital printing, where the image gets broken down into thousands of dots that overlap. Each dot corresponds to a value of CMYK, and these dots blend together to create a full-color image that looks seamless to the eye.
Because of the differences between the way the various color modes work, each mode has limits on which portions of the entire color gamut that it can reproduce. While all color modes can successfully reproduce the majority of colors there will be instances where one color model can reproduce a color that a different color can’t.
When designing for print you’ll want to use the CMYK color mode. And if you already have a document designed in RGB you’ll need to convert your RGB files to CMYK files. If you are unsure of the proper way to make the conversion or have problems with the conversion the prepress department at most printing companies will be happy to walk you through the process or even do the conversion process for you.
Spot color printing uses a premixed ink color. Also known as Pantone or PMS printing, this method is often used when the CMYK color process can’t accurately reproduce a given color. Or when brand color consistency is essential no matter what printing press is used. The Pantone color matching system allows you to visually see how a color will reproduce when printed which you can then specify for the printer to use that PMS spot color when running your job.
Spot printing is an excellent option if you need to get a perfect color match over a large number of products, but it can quickly become expensive. Each spot color has to be added to the press (in addition to the standard CMYK inks), and adding in more pigments will increase the cost.
Converting from Onscreen to Print Color Types
A common problem in graphic design is converting from an on-screen type to a printing type. Luckily, most high-end graphics tools like Photoshop and Illustrator have conversion options in place. You can use these to transition between CMYK and RGB, even in the middle of the project.
Since RGB values and CMYK values may not produce the same hue, you should expect some colors to look different. Often, some colors will be darker than in the original. By converting your project before sending it to the printer, you can correct these colors in CMYK and avoid nasty surprises.
Which One Should You Use?
Choosing the right color mode will depend largely on your project. If it’s an exclusively on-screen project, RGB is the gold standard. It provides the broadest range of colors and saturation, producing clear and vivid designs. It’s the most commonly used digital color mode, which means that apart from some minor variations due to display settings, you’ll get accurate color reproduction on every electronic device.
On the other hand, if you’re working on a project that will end up being printed, it’s best to work in CMYK. Doing so will ensure that you get accurate color reproduction when your project finally goes to press.
If you’re planning a large-scale project that includes color critical PMS specified colors then spot color Pantone printing may be the best option.
Understanding how different color modes produce colors can give you more control over your design. Once you’ve worked in a particular color mode for a while, you’ll gain a better understanding of how it translates to the end product, which will make your design process more efficient and accurate. You’ll also know which color type to work with, depending on the kind of project you undertake.
For a more detailed explanation of color modes used in the printing process as well as other tips and a glossary of printing terms download our free Printing Tips ebook.