First of all: what the heck is CMYK? Maybe you’ve seen this strange collection of letters before. Maybe you know exactly what it is. In case you don’t, CMYK is a shorthand way of talking about cyan, magenta, yellow and black. Don’t ask why it’s not CMYB. Maybe that sounds too much like BYOB. Anyway, it doesn’t matter.

What does matter is that these four “color values” are deemed by screen printers to be the best for full-color printing, especially on white. This isn’t surprising because CMYK was developed for printing on paper, which is usually white.

To achieve the right colors, we use a photo or other image and separate out the cyan, magenta, yellow and black. For printing, the colors are combined to match the colors in the photo or image. The result should be an image rich in color tones that closely match the original image.

By mixing the four colors, we can come up with a wide range of tones. This is accomplished by printing different densities of the basic colors. What the final image looks like depends on how much cyan, magenta and yellow are laid down on the substrate—the material being printed on.

Sound easy? Unfortunately, this explanation doesn’t take into account the substrate—the material being printed on. How thick and what color the substrate happens to be can make a big difference.

As everyone knows, garments and other printable items come in many colors. When they’re not white or at least quite light-colored, CMYK will probably need the addition of a couple of other colors to accurately reproduce the artwork.

Most often, the added colors are different kinds of white. To give the CMYK colors a solid background, an opaque white can be laid down so the more transparent CMYK ink doesn’t let the substrate color show through and muddy the image.

The opaque white used as a backdrop for the CMYK colors isn’t completely opaque, however, so it needs another white to make it bright enough for the brighter parts of the printed image to pop as they should. So another white screen has to be added.

As for substrate thickness and flexibility, a little variation can cause some big issues. Garments and other printable items come from all over the world. They’re made by different companies with different standards. They vary between manufacturers and even within lots.

These variations make CMYK printing a challenge. Different thicknesses—even slight differences—can vary the distance between the substrate surface and the screen. This can lead to greater saturation on some items and, possibly, color problems, where a cyan, magenta, yellow or black tint affects the whole image.

Here are the takeaways on CMYK, or four-color process, printing:

  • It’s best to print on light or white substrates
  • The image shouldn’t contain features, such as skin tones, in which slightly wrong coloring will be obvious
  • Use substrates that vary as little as possible in thickness, such as T-shirts

Simulated Process Printing

If you’re not printing on white, you might want to go with simulated process printing. It’s not CMYK, but it yields results that are close and has more flexibility.

Simulated process printing is a combination of four-color process and spot color printing (see Spot color and Pantone matching). It can still be expensive, but you can choose from a wider range of substrate colors.

If you have an intricate image you want to look its best, simulated process printing could be the way to go. It does require some extra care in creating the artwork, though.

To learn more about full-color CMYK screen-printing and working with us to create guaranteed great screen-printed garments and other items, contact us. We’d be happy to answer your questions.