Colour bar

A colour bar is a series of solid ink patches, typically representing cyan, magenta, yellow, and black, along with their various combinations. In pre-press workflows, these bars are included on print proofs and production sheets to allow operators to measure ink density and total area coverage.

The primary purpose of colour bar printing is quality control. By measuring the specific patches with a densitometer, printers can verify that their presses are meeting the standards defined by ISO 12647. This ensures that the final printed cards match the intended digital design, compensating for variations in paper type or ink formulation. It serves as a critical checkpoint before the full batch is cut.