CMYK and RGB Explained . . . (for the rest of us)

OK, if you are a graphic designer, you can probably skip this article, but if you are like many in the media field, you remain a bit glassy-eyed when you hear the terms CMYK or RGB used in describing the artwork of your projects.

For example, there are times when we here at Video Labs ask for your disc face or packaging artwork to be presented to us in RGB, and then there are times when we ask for it in CMYK.

What gives?

Well, here’s a brief starting primer:

CMYK = the complementary colors of Cyan, Magenta, Yellow plus the fourth color of Black. This is known as a “subtractive” color process, meaning that if you combine equal amounts of the three colors of Cyan, Magenta and Yellow, you will produce black. Some processes just stop there, but the addition of a fourth color, Black (K = Black) provides two advantages: 1) save having to use all three inks just to make black, and 2) this sole black ink can actually be a richer black than can be made from the mixture of the three other colors.

General rule #1: Printing processes utilize CMY or CMYK. (Hold that thought . . .)

RGB = the primary colors of Red, Green and Blue. This process is known as “additive,” because if you mix the three colors in equal amounts, you get white.

“Wait a minute,” you say. “If I mix red, green and blue ink together on a paper, it certainly is not going to come out white.”

This is true, but if you did it with colored lights, the results would produce a white lit object. And how about those red, green and blue pixels in your television or computer monitor? If all three are charged at the same time, the perceived result is white not black.

So general rule #2: RGB applies to lighting and digital displays of color.

But yes, here’s where it can get confusing. You rightly might ask, “Well then, I know that there are some RGB printers on the market. What’s that all about?” What’s going on there, is that for technical and economic reasons, those printers intake RGB artwork and then convert it to CMY or CMYK for the actual printing.

Whew, ok, that’s enough for now.

Let’s end this with the following summary rules:
• For disc face artwork on replicated CD/DVD projects, where we use offset or silk-screen printing, we will ask for CMYK artwork.
• For offset printing of packaging (like DVD wraps, etc.) we will also ask for CMYK artwork.
• For duplicated DVDs, where we use thermal transfer printing for disc faces, we will ask for RGB artwork, again, as stated above, even though it will be converted to CMY in printing. (As stated above, this printing process does not have a separate “K,” or black).
• And for digital printing of packaging (like DVD wraps, etc.) we will ask for RGB artwork. Again, the digital printer will convert it to CMYK.

Next time, we’ll touch on another term we often use with our clients, Pantone Matching System (PMS) colors, aka “spot” colors and the role that plays in printing.

We welcome your comments, and please feel free to contact us at Video Labs (301-217-0000) with any further questions.