Offset printing relies on a process called color separation to create accurate and consistent colors in printed materials.
A single image or design is divided into four separate color plates: cyan (C), magenta (M), yellow (Y), and black (K). Each plate corresponds to a different ink color.
- Cyan: Teal
- Magenta: Pinkish Red
- Yellow: Primary Yellow
- Black: Pure Black
During printing, the individual plates are stacked in sequence and aligned with great precision. As they pass through the press, the inks from each plate are transferred onto the paper, creating the final image.
When the inks overlap, new colors are created:
- C + M = Blue
- C + Y = Green
- M + Y = Red
- C + M + Y = Brown
To ensure accurate color reproduction, a proof is created from the separated plates. This proof is used to compare the printed colors to the original design and make any necessary adjustments.
Additionally, printing presses are calibrated to ensure that the ink colors are consistent throughout the print run.
For specific colors that cannot be created using the CMYK process, the Pantone Matching System (PMS) is used. PMS inks are premixed and designed to match specific color swatches.
In offset printing, PMS inks can be added as an additional plate to the standard CMYK process, allowing for a wider range of colors.