Overall Findings
The quickest way to explain the difference between the two is that RGB is for the web, and CMYK is for prints. It’s a little more complicated than that, though, so let’s take a close look at the color spectrums.
RGB Pros and Cons
RGB stands for red, green, and blue—the three colors that can be mixed to produce different colors. It’s an additive color spectrum that relies on adding different amounts of the three colors to make different colors. The RGB spectrum has 256 levels of brightness, which in turn produce 16,777,216 (256 x 256 x 256) color possibilities. When you take a photograph on a DSLR, the camera composes the shot using an RGB spectrum. Computer monitors also work in RGB, so it’s easy for users to expect what they see on an LCD screen will be what they see on a monitor. Therefore, RGB is the industry default for DSLRs and computer monitors, because it allows colors to be viewed true-to-life on screen.
CMYK Pros and Cons
CMYK stands for cyan, magenta, yellow, and black. It’s a subtractive color spectrum that uses those colors as filters to subtract various amounts of red, green, and blue from white light to produce different colors. Therefore, an image displayed on a computer monitor might not match a print, unless the RGB spectrum is converted to CMYK. Although many printers convert from RGB to CMYK automatically, the process is not perfect. RGB doesn’t have a dedicated black channel, so blacks often appear too rich.
So Which Should You Choose?
Whether you go with RGB or CMYK largely depends on the medium you’re working with. If you’re going digital, you’ll probably want to use RGB. If you plan on printing your work, you might want to use CMYK. Most desktop printers in homes and offices use CMYK inks. The printing technology in both software applications and printers does a nice job of automatically converting RGB colors into CMYK. For the most part, you don’t have to worry about conversion on a home printer. If you find that your blacks are not quite right, however, convert to see if that helps. Although some commercial printers might ask you to convert a photograph to CMYK, it’s not common. This is particularly true when using a photo printing lab. Their software and technicians can handle most color challenges to produce the best photographic prints possible. They want to make the customer happy and know that not everyone has a full understanding of the technology involved. If you take your work to a dedicated graphics printer for items such as postcards and brochures, they might ask for the image in CMYK. This is because it’s the format that they always work with. CMYK, also known as four-color printing, dates back to the days before digital technology was imagined.
