The printing process is based on four colors of ink: Cyan, Magenta, Yellow and Black (CMYK). Each color is added separately as the paper passes through the press. This is why you may hear it referred to as a Four Color Process or Four Color Printing. Also why you may see your printer refer to a file that will be printed on each side as 4/4. Meaning, four inks on the front and four on the back. A job to be printed only on the front would be 4/0, etc.
When designing, you need to make sure you are using CMYK Color during four specific times: New Document Setup, Swatches and Color Palettes, Embedding Photos and Artwork, during PDF Export.
What happens when you send art as RGB instead of CMYK?
Printing presses only understand color in terms of CMYK ink percentages. RGB images store the color information by how much light to use. Since printers don’t understand color this way, anything RGB will be automatically converted to the closest CMYK match. Some colors in the RGB Spectrum cannot be reached with ink. In order to make sure you know exactly what your job will look like, design only in the CMYK color mode.
CMYK Color
Each color in the printing process is produced by a special blend of the four inks: Cyan, Magenta, Yellow and Black. It is a subtractive process, white from the paper is subtracted as dots of ink are added to it.
*Make sure you design using the right Color Panel and Swatch Libraries. If you begin working with the wrong Color Panel, Color Guide, or Swatch Library, you may be looking at colors in the RGB color spectrum that can’t be reproduced by the CMYK color process.
RGB Color
Web based images have an RGB color mode. Monitors display color by using Red, Green and Blue light. It is an additive process, when all three lights are combined you get white light. RGB can reproduce a wider range of colors than what can be reached using inks.
*The Web Color Palette is much larger than the palette for print. Many of these colors are unable to be reproduced by ink.
PANTONE + Spot Colors
Many brands have specific PANTONE Colors they like to use. Consult this guide to learn more about using PANTONE Colors and Spot Colors.
Next Step: PANTONE and Spot Colors
For PANTONE, leave spot colors active. Otherwise, use CMYK. Know when and how to use Spot Colors.