CMYK stands for Cyan Magenta Yellow blacK
These are the most common ink colors used in both offset and digital printing. These color can be combined (printed on top of each other) to produce certain spectrum of colors (this is also known as ColorSpace) It is typically used when producing a lot of colors on a sheet and defiantly any color photographs. Your printer may call it “Process Printing”, “Full Color Printing” or “Four Color Printing” all of these terms refer to blending the CMYK inks to produce color.
One question I always get from the Art Major is why we use black? Theoretically, you should only need CMY to mix to get black and they are right. The issue is that the black that is created by mixing the three colors do not create a deep black, which is why we added a true black for density in photographs and strong crisp black text. See the colors below…
Please note that although Cyan looks “blue” it is not the same, nor is the Magenta “red”…you will see what I mean when I discuss the next ColorSpace RGB.