Whether you’re a designer or a business owner working with a designer, knowing whether to choose RGB or CMYK is essential. Your choice of “color mode” will determine how well and how true to color your images print or display, so a basic understanding of the difference can improve the quality of your project.
Put simply, RGB refers to colored light, and should be used for anything dealing with the web. CMYK refers to colored ink, and should be used in any printed material.
First, let's dive a little deeper into web colors. RGB (Red, Green, Blue) is the typical “color space” used by electronic displays, monitors, TVs, mobile devices, etc. The red, green, and blue components are the amounts of red, green, and blue light an RGB color contains. The amounts are measured in values ranging from 0 to 255.
For example, here is a nice minty green along with its corresponding RGB and CMYK values >>>
Digital displays have a larger “color gamut” than can be achieved in print. This is why a computer or TV can display a million more colors than any printed image can.
For those who may have had to pause mid sentence to try and figure out what color gamut means, let me explain. A color gamut is a certain complete subset of colors. In common usage, color gamut refers to the subset of colors that can be accurately represented in a given circumstance – for example, in print. Some times people will notice that something looks different on screen than it does on paper, and that is because both computer monitors and printers have different limited color ranges, or color gamuts.
As a result, if you choose an RGB color for web use that is outside of the CMYK color gamut, you won’t be able to print in the exact same shade (Photoshop will warn you if this is the case). As you can imagine, this has implications for important branding pieces like logos.
When dealing with RGB, you’ll also want to keep in mind that different monitor manufacturers and individual screen settings may cause each screen to represent colors differently. In most cases, though, the average naked eye won't be able to tell the difference.
Now, let’s dive into the color model used for print. CMYK refers to the four colored inks (Cyan, Magenta, Yellow, and Black) used to create a color, and is also known as four-color or process color.
Here’s a fun fact for you history buffs: back in the printing press days, to achieve a wider range of colors, each ink had its own plate. The printing process consisting of laying one color down and waiting for it to dry, laying the next color down and waiting for it to dry, and repeating this process with all four plates – hence, “four-color.”
Today, the four colors of CMYK are still mixed together to make up other colors, and each component is measured in a percentage from 0 to 100. Note that the percentages used for each ink will not equal 100%; the values represents the percentage of ink coverage (remember the four color plates of the printing press?).
To summarize, when it comes to deciding which color mode to use, first decide what the final output will be. If the output will be on a digital display, use RGB, but if the final output is a printed piece, CMYK is the best option.
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